Photolabile Compounds

ABSTRACT

The present invention describes Photolabile Compounds methods for use of the compounds. The Photolabile Compounds have a photoreleasable ligand, which can be biologically active, and which is photoreleased from the compound upon exposure to light. In one embodiment, the light is visible light, which is not detrimental to the viability of biological samples, such as cells and tissues, in which the released organic molecule is bioactive and can have a therapeutic effect.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional PatentApplication No. 60/532,976, filed Dec. 29, 2003, which is herebyincorporated by reference herein in its entirety.

The United States Government may have certain rights in the presentinvention pursuant to a contract with NYSTAR (NYSTAR Contract No.C000082).

This patent disclosure contains material which is subject to copyrightprotection. The copyright owner has no objection to the facsimilereproduction by anyone of the patent document or the patent disclosure,as it appears in the U.S. Patent and Trademark Office patent file orrecords, but otherwise reserves any and all copyright rights.

FIELD OF THE INVENTION

The present invention relates generally to novel Photolabile Compoundsand methods for uncaging an organic molecule, such as a bioactivemolecule, which can have a variety of uses both in vitro and in vivo.

BACKGROUND OF THE INVENTION

Photolabile protecting groups, which are also called caging groups, areclasses of protecting groups that are particularly useful in thebiological sciences. Because light can be controlled with precision bothspatially and temporally, cleaving a protecting group from a bioactivemolecule allows release, or uncaging, of the molecule. Protecting groupstypically mask or conceal charged (for example, carboxylate orphosphate) or polar (for example, amine, hydroxyl, or sulfhydryl) groupson the compounds. Frequently such functionalities increase thehydrophobicity and membrane permeability of the protected molecules.Prior to photolysis, the Photolabile Compounds are typically chemicallyor biologically inactive because at least one of the compounds' mainfunctionalities is blocked. The activity of the molecule can betriggered by a pulse of light, thereby releasing the molecule from thephotoreleasable compound. Thus, photolabile protecting groups can beremoved from a protected compound by irradiation, for example, tocontrol the release of the compound when and where desired, either invivo or in vitro.

Commercially available Photolabile Compounds typically requireultraviolet (UV) light to remove the compounds from the cage. However,UV light can cause damage to organs, tissues and cells, thus making UVlight detrimental for in vivo use. Thus, there is a need in the art toutilize new Photolabile Compounds having ligands that can be releasedusing light other than UV light, particularly for in vivo applications.The present invention provides novel Photolabile Compounds and methodsfor using the compounds, which provide advantages over currentlyavailable compounds that are photolabile using only UV light.

SUMMARY OF THE INVENTION

It is an aspect of the present invention to provide novel PhotolabileCompounds that protect an organic molecule, such as a bioactivemolecule. Upon exposure to light, the organic molecule is released, andis useful in the methods described herein.

Accordingly, the present invention provides compounds of Formula I:

wherein:

each L¹ is independently an organic molecule having:

-   -   (a) a 5-membered monocyclic aromatic ring, one of the ring's        members being a nitrogen atom that forms a bond with Os;    -   (b) a 6-membered monocyclic aromatic ring, one of the ring's        members being a nitrogen atom that forms a bond with Os;    -   (c) an 8-10-membered bicyclic ring, one of the bicyclic rings        being aromatic and having a nitrogen atom member that forms a        bond with Os;    -   (d) an —NH₂ group whose nitrogen atom forms a bond with Os; or    -   (e) a —COOH group, one of whose oxygen atoms forms a bond with        Os;

L² is (R²)₃P, (R²⁰)₃P, or L¹, wherein each R² is independently —C₁-C₁₈alkyl, —C₃-C₈ cycloalkyl, or phenyl, and m is 2; or L² is —CN and m is1;

R¹-R⁸ are independently-H, —C₁-C₁₈ alkyl, —NH₂, —COOH, —(C₁-C₁₈alkyl)-O—(C₁-C₁₈ alkyl), or —OC(O)(C₁-C₁₈ alkyl); and

X is Cl⁻, F⁻, Br⁻, I⁻, PF₆ ⁻, CF₃SO₃ ⁻, (C₁-C₁₈ alkyl)-CO₂ ⁻, or (C₁-C₁₈alkyl)-SO₃ ⁻.

In another aspect, the present invention provides compounds of FormulaII:

wherein M is Ru or Os;

each L¹ is independently an organic molecule having:

-   -   (a) a 5-membered monocyclic aromatic ring, one of the ring's        members being a nitrogen atom that forms a bond with M;    -   (b) a 6-membered monocyclic aromatic ring, one of the ring's        members being a nitrogen atom that forms a bond with M;    -   (c) an 8-10-membered bicyclic ring, one of the bicyclic rings        being aromatic and having a nitrogen atom member that forms a        bond with M;    -   (d) an —NH₂ group whose nitrogen atom forms a bond with M; or    -   (e) a —COOH group, one of whose oxygen atoms forms a bond with        M;

L² is (R²)₃P, (R²⁰)₃P, or L¹, wherein each R² is independently —C₁-C₁₈alkyl, —C₃-C₈ cycloalkyl, or phenyl, and m is 2; or L² is —CN and m is1;

R¹-R⁸ are independently —H, —C₁-C₁₈ alkyl, —NH₂, —COOH, —(C₁-C₁₈alkyl)-O—(C₁-C₁₈ alkyl), or —OC(O)(C₁-C₁₈ alkyl); and

X is Cl⁻, F⁻, Br⁻, I⁻, PF₆ ⁻, CF₃SO₃ ⁻, (C₁-C₁₈ alkyl)-CO₂ ⁻, or (C₁-C₁₈alkyl)-SO₃ ⁻.

In another aspect, the present invention provides compounds of FormulaIII:

wherein:

each L¹ is independently an organic molecule having:

-   -   (a) a 5-membered monocyclic aromatic ring, one of the ring's        members being a nitrogen atom that forms a bond with Co;    -   (b) a 6-membered monocyclic aromatic ring, one of the ring's        members being a nitrogen atom that forms a bond with Co;    -   (c) an 8-10-membered bicyclic ring, one of the bicyclic rings        being aromatic and having a nitrogen atom member that forms a        bond with Co;    -   (d) an —NH₂ group whose nitrogen atom forms a bond with Co; or    -   (e) a —COOH group, one of whose oxygen atoms forms a bond with        Co;

L² is (R²)₃P, (R²⁰)₃P, or L¹, wherein each R² is independently —C₁-C₁₈alkyl, —C₃-C₈ cycloalkyl, or phenyl, and m is 3; or L² is —CN, —Cl, Br,—I or —N₃ and m is 2;

R¹ to R⁴ are independently —C₁-C₁₈ alkyl; and

X is Cl⁻, F⁻, Br⁻, I⁻, PF₆ ⁻, CF₃SO₃ ⁻, (C₁-C₁₈ alkyl)-CO₂ ⁻, or (C₁-C₁₈alkyl)-SO₃ ⁻.

In another aspect, the present invention provides compounds of FormulaIVa:

wherein:

each L¹ is independently an organic molecule having:

-   -   (a) a tetrazolyl group, one of its nitrogen atoms forming a bond        with Ru;    -   (b) nicotine or caffeine, whose pyridyl nitrogen atom forms a        bond with Ru;    -   (c) an 8-10-membered bicyclic ring, one of the bicyclic rings        being aromatic and having a nitrogen atom member that forms a        bond with Ru;    -   (d) an —NH₂ group whose nitrogen atom forms a bond with Ru; or    -   (e) a —COOH group, one of whose oxygen atoms forms a bond with        Ru;

L² is (R²)₃P, (R²⁰)₃P, or L¹, wherein each R² is independently —C₁-C₁₈alkyl, —C₃-C₈ cycloalkyl, or phenyl, and m is 2; or L² is —CN and m is1.

R¹-R⁸ are independently —H, —C₁-C₁₈ alkyl, —NH₂, —COOH, —(C₁-C₁₈alkyl)-O—(C₁-C₁₈ alkyl), or —OC(O)(C₁-C₁₈ alkyl); and

X is Cl⁻, F⁻, Br⁻, I⁻, PF₆ ⁻, CF₃SO₃ ⁻, (C₁-C₁₈ alkyl)-CO₂ ⁻, or (C₁-C₁₈alkyl)-SO₃ ⁻.

In another aspect, the present invention provides compounds of FormulaIVb:

wherein:

L¹ is 4-aminopyridine (4-AP), whose pyridyl nitrogen atom forms a bondwith Ru;

L² is (R²)₃P, (R²O)₃P, or L¹, wherein each R² is independently —C₁-C₁₈alkyl, —C₃-C₈ cycloalkyl, or phenyl, and m is 2; or L² is —CN and m is1;

R¹-R⁸ are independently —H, —C₁-C₁₈ alkyl, —NH₂, —COOH, —(C₁-C₁₈alkyl)-O—(C₁-C₁₈ alkyl), or —OC(O)(C₁-C₁₈ alkyl); and

X is Cl⁻, F⁻, Br⁻, I⁻, PF₆ ⁻, CF₃SO₃ ⁻, (C₁-C₁₈ alkyl)-CO₂ ⁻, or (C₁-C₁₈alkyl)-SO₃ ⁻.

In another aspect, the present invention provides compounds of FormulaV:

wherein:

M¹ is Li⁺, Na⁺, or K⁺; M² is Fe, Ru, or Os;

and L¹ is independently an organic molecule having:

(a) a 5-membered monocyclic aromatic ring, one of the ring's membersbeing a nitrogen atom that forms a bond with M²;

(b) a 6-membered monocyclic aromatic ring, one of the ring's membersbeing a nitrogen atom that forms a bond with M²;

(c) an 8-10-membered bicyclic ring, one of the bicyclic rings beingaromatic and having a nitrogen atom member that forms a bond with M²;

(d) an —NH₂ group whose nitrogen atom forms a bond with M²; or

(e) a —COOH group, one of whose oxygen atoms forms a bond with M².

A compound of Formula I-V (“a Photolabile Compound”) releases L¹ uponexposure to light.

In another aspect, the present invention provides a compositioncomprising an effective amount of a Photolabile Compound and aphysiologically acceptable carrier, vehicle, diluent, or excipient.

In another aspect, the present invention provides a vessel containing aPhotolabile Compound.

In yet another of its aspects, the present invention provides a kitcomprising a Photolabile Compound and instructions for use.

Another aspect of the present invention provides methods for releasingan organic molecule from a Photolabile Compound, comprising exposing aPhotolabile Compound to light under conditions sufficient to release theorganic molecule.

In yet another aspect, the present invention provides a method forprotecting an organic molecule from an effect of an enzyme, comprisingallowing the organic molecule and a compound of Formula I′:

wherein m is 2; R¹-R⁸, the organic molecule, and X are as described forFormula I, to react under conditions sufficient to make a compound ofFormula I.

In another aspect, the present invention provides methods for protectingan organic molecule from an effect of an enzyme, comprising allowing theorganic molecule and a compound of Formula II′:

wherein m is 2; and R¹-R⁸, the organic molecule, and X are as describedfor Formula II, to react under conditions sufficient to make a compoundof Formula II.

In another aspect, the present invention provides methods for protectingan organic molecule from an effect of an enzyme, comprising allowing theorganic molecule and a compound of Formula III′:

wherein m is 3; and R¹-R⁴, the organic molecule, and X are as describedfor Formula III, to react under conditions sufficient to make a compoundof Formula III.

In another aspect, the present invention provides methods for protectingan organic molecule from an effect of an enzyme, comprising allowing theorganic molecule and a compound of Formula IVa′:

wherein m is 2; and R¹-R⁸, the organic molecule, and X are as describedfor Formula IVa, to react under conditions sufficient to make a compoundof Formula IVa.

In another aspect, the present invention provides methods for protectingan organic molecule from an effect of an enzyme, comprising allowing theorganic molecule and a compound of Formula IVb′:

wherein m is 2; and R¹-R⁸, the organic molecule, and X are as describedfor Formula IVb, to react under conditions sufficient to make a compoundof Formula IVb.

In another aspect, the present invention provides methods for protectingan organic molecule from an effect of an enzyme, comprising allowing theorganic molecule and a compound of Formula V′:

wherein M¹ and the organic molecule are as described for Formula V, toreact under conditions sufficient to make a compound of Formula V.

In yet another aspect, the present invention provides a method formaking an organic molecule bioavailable to a subject in need of theorganic molecule, comprising administering a Photolabile Compound to thesubject; and exposing the compound to light under conditions sufficientto release the organic molecule from the compound.

In another aspect, the present invention provides methods for assayingan organic molecule, comprising: (a) exposing a Photolabile Compound anda biological sample to light under conditions sufficient to release theorganic molecule from the Photolabile Compound, and (b) determining aneffect of the organic molecule on the biological sample.

Additional aspects, features and advantages afforded by the presentinvention will be apparent from the detailed description, figures, andexemplification hereinbelow.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 depicts a partial ¹H NMR spectra of [Ru(bpy)₂(4AP)₂]Cl₂, asdescribed herein (Example 1), showing the signals corresponding to the4-AP meta hydrogens. m1: in [Ru(bpy)₂(4AP)₂]²⁺; m2: in[Ru(bpy)₂(H₂O)(4AP)₂]²⁺; m3: in free ligand 4-AP.

FIG. 2 (Top) shows action potentials (spikes) recorded in a medicinalleech (Hirudo medicinalis) neuron for saline and solutions of[Ru(bpy)₃]Cl₂ and [Ru(bpy)₂(4AP)₂]Cl₂ (Bottom): Frequency of the spikes.Arrows indicate irradiation with Xe flashlamp. (Middle): Composition ofthe extracellular medium.

FIG. 3 shows cyclic voltammetry (CV) profile of [Ru(bpy)₂(4AP)₂]Cl₂ inwater. The supporting electrolyte was KNO₃ (1 M). dE/dt=100 mV/s inglassy carbon electrode.

FIGS. 4A and 4B show NMR spectra of [Ru(bpy)₂(4AP)₂]Cl₂ in D₂O before(FIG. 4A) and after (FIG. 4B) irradiation. Bruker 500 MHz.

FIG. 5 shows the UV-visible (UV-vis) spectra of Ru(bpy)₂(4AP)₂ beforeand after complete photolysis. The photoproducts after exposure to lightwere Ru(bpy)₂(4AP)(H₂O) and free 4AP. The complex did not undergo darkdecomposition for more than 20 hours. After 7 hours in the dark, theirradiated solution showed less than 4% of 4AP recombination.

FIG. 6 shows a UV-vis spectrum of the filter used for the ganglionirradiation experiments as described in Example 3.

FIGS. 7A and 7B show action potentials and frequency of the spikesobtained in studies of medicinal leech (Hirudo medicinalis) ganglia.FIG. 7A shows a recording of Retzius neuron voltage activity duringperfusion of free 4AP on the leech ganglia. [4AP]=0, 10, 20 and 50 mM.Flow rate=1 ml/min. Carrier: saline solution, as described in Example 3.FIG. 7B shows the recording of Retzius neuron activity during exposureto a 0.1 msec flash of green light through the filter of FIG. 6. Flowrate=1 ml/min. Carrier: saline solution, as described in Example 3.Pulse energy: 0.5 J.

FIGS. 8A and 8B relate to spectra changes of [Ru(bpy)₂(4AP)₂]Cl₂ duringexposure to light. FIG. 8A: spectrum changes of [Ru(bpy)₂(4AP)₂]Cl₂during irradiation with 473 nm laser light. Power: 6.39 mW continuous.Initial concentration of [Ru(bpy)₂(4AP)₂]Cl₂: 27.9 μM. A(473 nm)=0.18.FIG. 8B: Fraction of [Ru(bpy)₂(4AP)(H₂O)]²⁺. as a function ofirradiation time obtained from the spectra depicted in FIG. 8A.

FIG. 9 shows a graph of photoreleased 4AP versus pulse energy. The lightsource was pulsed Xe lamp with a bandpass filter. [Ru(bpy)₂(4AP)₂]Cl₂=44μM; Vol.=3 mL. The data were obtained from UV-vis spectra analysis.

FIG. 10 shows several two-photon fluorescence images of[Ru(bpy)₂(TzGly)(py)]Cl₂ at different excitation wavelengths.(Magnification: ˜20×).

FIG. 11 depicts a graph of total two-photon fluorescence versusexcitation wavelength of [Ru(bpy)₂(4AP)₂]Cl₂.

FIG. 12 presents a UV-vis spectrum of TzGly before and after irradiationwith 400-600 nm light.

FIGS. 13A and 13B: FIG. 13A depicts the structure of TzGly. FIG. 13Bdemonstrates the spiking of a mouse cortical neuron caused by theaddition of TzGly (1 μM) to neuron via perfusion. The measurementresults were obtained by the whole-cell patch-clamp method, as known andused in the art.

FIGS. 14A-G relate to experiments performed on neurons contacted with[Ru(bpy)₂(TzGly)(py)]Cl₂. FIGS. 14A, B and C show fluorescent-imagemicrographs of a neuron, including magnified views of dendritic spines.FIG. 14D shows the effect of laser irradiation (˜40 mW) on the spikingof a single neuron in the presence of [Ru(bpy)₂(TzGly)₂]Cl₂.Concentration of [Ru(bpy)₂(TzGly)₂]Cl₂=100 μM; Pulse length: 10 ms;Power: 40 mW; Wavelength: 720 nm. FIGS. 14E-G relate to experimentscarried out as controls to the experiments of FIGS. 14A-D. FIGS. 14E andF show magnified views of the dendritic spines of a neuron. FIG. 14Gpresents a plot showing the effect of laser irradiation on a controlneuron in the absence of [Ru(bpy)₂(TzGly)₂]Cl₂. No increased activity isobserved. Pulse length: 10 ms; Power: 40 mW; Wavelength: 720 nm.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates generally to Photolabile Compoundscomprising organic molecules and methods for using the PhotolabileCompounds. The organic molecules can be biologically active. In oneembodiment of this invention, an organic molecule, e.g., a biologicallyactive molecule, is protected and subsequently released upon exposure tolight, advantageously, visible light.

In contrast to known methods, visible light, e.g., a visible lightpulse, can be used to release an organic molecule from a PhotolabileCompound. Thus, in the present methods, samples, e.g., organs, tissuesor cells, or subjects to which a Photolabile Compound is administered,undergo only minimal, if any, exposure to UV radiation, which hasdetrimental effects on cellular components and, ultimately, on cellgrowth and viability.

In accordance with the present invention, and without wishing to bebound by theory, the metal (M)-organic molecule bond is normally weakerthan a covalent σ bond, and therefore can be broken using a lower energyirradiation. Further in accordance with this invention, and withoutwishing to be bound by theory, the energy required for the release of anorganic molecule by exposure to light is relatively low. In thePhotolabile Compounds of this invention, the organic molecule isphotoreleased by irradiation of the Photolabile Compound using light asdescribed herein.

Also, according to this invention, photorelease can occur in vivo or ina biological sample, e.g., a body fluid, a body sample, such as an organor tissue sample, in living cells and in the body. Thus, the PhotolabileCompounds are especially valuable for in vivo biological applications,such as treatments for various diseases, conditions and disorders of thebody. The use of Photolabile Compounds as described herein allowsprecise control of the onset of a bioactive function or a bioactivity inthe body, for example, in living organs, tissues, and cells, i.e.,within microseconds to milliseconds, with minimal harm to a biologicalsample, or to the body or its organ, tissue and cellular components. Inaddition, exposure of a biological sample to light can be localized tothe site where an organic molecule is needed or desired. This isparticularly beneficial for administration to a subject, particularly ahuman patient.

The Photolabile Compounds are also suitable for use in non-biologicalsystems, such as in solar cells, photocells, or an optical memory, e.g.,a three dimensional optical memory.

In one embodiment, the invention encompasses compounds of Formula I:

wherein:

R¹-R⁸, L¹, L², X and m are as defined above for the compounds of FormulaI.

In another embodiment, the invention encompasses a compound of FormulaII:

wherein:

R¹-R⁸, L¹, L², X, M and m are as defined above for the compounds ofFormula II.

In another embodiment, the invention encompasses a compound of FormulaIII:

wherein:

R¹-R⁴, L¹, L², X and m are as defined above for the compounds of FormulaIII.

In another embodiment, the invention encompasses a compound of FormulaIVa:

wherein:

R¹-R⁸, L¹, L², X and m are as defined above for the compounds of FormulaIVa.

In another embodiment, the invention encompasses a compound of FormulaIVb:

wherein:

R¹-R⁸, L¹, L², X and m are as defined above for the compounds of FormulaIVb.

In another embodiment, the invention encompasses a compound of FormulaV:

wherein M¹, M², and L¹ are as defined above for the compounds of FormulaV.

The Photolabile Compounds of Formulas I, II, IVa, IVb and V can existsin a cis or trans configuration. Accordingly, Formulas I, II, IVa, IVband V encompass both cis and trans forms of the Photolabile Compounds.

It is to be understood the Photolabile Compounds of Formula III existonly in a trans configuration.

In the compounds of Formulae I-IVb, —(C₁-C₁₈) alkyl refers to asaturated straight or branched non-cyclic hydrocarbon having 1 to 18carbon atoms. Representative saturated straight chain —(C₁-C₁₈) alkylsinclude -methyl, -ethyl, -n-propyl, -n-butyl, -n-pentyl, -n-hexyl,-n-heptyl, -n-octyl, -n-nonyl, -n-decyl, -n-undecyl, -n-dodecyl,-n-tridecyl, -n-tetradecyl, -n-pentadecyl, -n-hexadecyl, -n-heptadecyland -n-octadecyl. Representative saturated branched —(C₁-C₁₈) alkylsinclude -isopropyl, -sec-butyl, -isobutyl, -tert-butyl, -isopentyl,-2-methylbutyl, -3-methylbutyl, -2,2-dimethylbutyl, -2,3-dimethylbutyl,-2-methylpentyl, -3-methylpentyl, -4-methylpentyl, -2-methylhexyl,-3-methylhexyl, -4-methylhexyl, -5-methylhexyl, -2,3-dimethylbutyl,-2,3-dimethylpentyl, -2,4-dimethylpentyl, -2,2-dimethylhexyl,-2,3-dimethylhexyl, -2,4-dimethylhexyl, -2,5-dimethylhexyl,-2,2-dimethylpentyl, -3,3-dimethylpentyl, -3,3-dimethylhexyl,-4,4-dimethylhexyl, -2-ethylpentyl, -3-ethylpentyl, -2-ethylhexyl,-3-ethylhexyl, -4-ethylhexyl, -2-methyl-2-ethylpentyl,-2-methyl-3-ethylpentyl, -2-methyl-4-ethylpentyl,-2-methyl-2-ethylhexyl, -2-methyl-3-ethylhexyl, -2-methyl-4-ethylhexyl,-2,2-diethylpentyl, -3,3-diethylhexyl, -2,2-diethylhexyl,-3,3-diethylhexyl and the like.

In the compounds of the present invention, —(C₃-C₈) cycloalkyl refers toa saturated cyclic hydrocarbon having from 3 to 8 carbon atoms.Representative —(C₃-C₈) cycloalkyls include -cyclopropyl, -cyclobutyl,-cyclopentyl, -cyclohexyl, -cycloheptyl and -cyclooctyl hydrocarbons.

An amino acid group, such as an α-amino acid, is an organic moleculehaving an amino group (—NH₂) and a carboxylic acid group. An amino acidcan be one of the 20 common α-amino acids (Gly, Ala, Val, Leu, Ile, Ser,Thr, Asp, Asn, Lys, Glu, Gln, Arg, His, Phe, Cys, Trp, Tyr, Met andPro), or another naturally occurring amino acid, such as norleucine,ethylglycine, ornithine, gamma-amino butyric acid, and phenylglycine.

Examples of a 6-membered monocyclic aromatic ring, wherein one of thering's members is a nitrogen atom, include a pyridyl, pyrimidinyl,pyridazinyl and pyrazinyl ring.

Examples of a 5-membered monocyclic aromatic ring, wherein one of thering's members is a nitrogen atom, include a pyrrolyl, imidazolyl,pyrazolyl, triazolyl, tetrazolyl, oxazolyl, oxadiazolyl, thiazolyl andthiadiazolyl ring.

Examples of an 8-10-membered bicyclic aromatic ring, wherein one of therings is aromatic and has a nitrogen atom member, include anindolizinyl, isoindolyl, 3H-indolyl, indolyl, indazolyl, purinyl,quinolyl, isoquinolyl, phthalazinyl, naphthyridinyl, quinoxalinyl,1,3,7-trimethyl-2,6-dioxopurinyl, quinazolinyl, cinnolinyl, pteridinyl,6-amino-1H-purinyl and 2-aminohypoxanthinyl bicyclic aromatic ring.

In general terms, illustrative examples of organic molecules useful inthe present Photolabile Compounds embrace a variety of agents, such aspharmaceutical agents, small molecules, drugs, neurochemicals, peptides,proteins, and chemotherapeutic agents, as nonlimiting examples.

Illustrative organic molecules can further include luciferin, enzymeinhibitors, fatty acids (e.g., arachidonic acid), protein kinase Cactivators (e.g., dioctanoylglycerol), tubulin assembly promoters (e.g.,paclitaxel), antibiotics (e.g., penicillins or A23187),neurotransmitters (e.g., L-glutamic acid, aspartic acid,carbamylcholine, dopamine, epinephrine, GABA, glutamic acid, glycine,haloperidol, isoproterenol, kainic acid, NMDA, NMDA receptor antagonistMK-801, norepinephrine, phenylephrine, propranolol), 4-aminopyridine(4AP), serotonin (5 hydroxytriptamine, 5HT), (RS)-(tetrazol-5-yl)glycine (TzGly),tetrazolyl-α-amino-3-hydroxy-5-methyl-4-isoxazoleproprionic acid((tetrazol-5-yl) AMPA), nicotine, nicotinic acid, isoxazole, andfluorescent dyes (e.g., fluorescein, HPTS, rhodamines, succinimidylesters and sulfosuccinimidyl esters of carboxy-Q-rhodamine, or RhodamineGreen), nucleotides (e.g., ATP, ADP, cAMP, GDP, GTP, cGMP, GTP-γ-S,GDP-β, 8-substituted derivatives of cAMP or cGMP, e.g., 8-bromo-cAMP,8-bromo-cGMP, 8-chloro-cAMP, 8-chloro-cGMP, 8-parachlorophenylthio(cCPT) cAMP or cGMP, phosphates (e.g., phosphates, phosphate esters),phenylphosphate (PPh₃), Py, nucleosides, nucleoside derivatives,nucleotide derivatives (e.g., cADP-ribose, 8-amino-cADP ribose, or8-bromo-cADP-ribose), cyclitols (e.g., inositol), cyclitol phosphates(e.g., myo-inositol phosphate, myo-inositol-1,4,5-triphosphate,myo-inositol-1,3,4,5-tetrakisphosphate, ormyo-inositol-3,4,5,6-tetrykisphosphate), NO (e.g., from the decomposablecompound HON═N(O) (Net₂)), chelants (e.g., EDTA, EGTA), and ionophores(e.g., nigericin). The organic molecule can be cell permeant, asdescribed, for example, in Furuta et al., Biochem. Biophys. Res.Commun., 228:193-198 (1996).

Especially useful examples of organic molecules include adenosine5′-diphosphate ADP; adenosine 5′-triphosphate ATP; adenosine5′-monophosphate AMP; aminobutyric acid; L-glutamic acid; cyclicadenosine 5′-diphosphate ribose; adenosine 3′,5′-cyclicmonophosphate;fluorescein; methyl-D-aspartic acid; tyramine; tryptophan;4-aminopyridine (4AP); epinephrine; norepinephrine; dopamine; serotonin(5 hydroxytriptamine, 5HT); (RS)-(tetrazol-5-yl) glycine (TzGly), whichis a potent N-methyl-D-aspartate receptor (NMDA) agonist;tetrazolyl-α-amino-3-hydroxy-5-methyl-4-isoxazoleproprionic acid((tetrazol-5-yl) AMPA); caffeine and nicotine.

In accordance with this invention, the organic molecule ligandsglutamate, gamma aminobutyric acid (GABA), alaninate, glycinate and thelike have been demonstrated to photorelease from a Photolabile Compoundafter exposure to visible light; such Photolabile Compounds are stablein solutions in addition to water. Organic molecules having an —NH₂group or an —COOH group are preferably released in solvents other thanwater, for example, alcohol (e.g., methanol, ethanol), acetone, etc.

The Photolabile Compounds of Formulas I, II, IVa and IVb where L₂ isother than L¹ can be made by allowing about a molar equivalent ofM(bdt)₂Cl₂, where M is Os or Ru and bdt is bipyridine or phenanthrolinesubstituted with an R₁-R₈ group as defined in Formula I, II, IVa or IVb,to react with about a molar equivalent of an organic molecule in water,ethanol, methanol, isopropyl alcohol, ethylene glycol, acetone,methylene chloride or a mixture thereof at reflux under nitrogen. Afterabout 4 to about 8 hours, the resultant solution is cooled and to it isadded at least about an equivalent of L₂. The resultant mixture isheated at reflux for about 4 to about 20 h. After cooling to roomtemperature, the resultant solution is diluted with water, and to it isadded excess NH₄ PF₆. The resultant precipitate is filtered, purifiedvia silica-gel chromatography, dried and dissolved in acetone.(n-Bu)₄NH₄ ⁺X, wherein X is defined in Formula I, II, IVa or IVb, isadded to the acetone solution, and the resultant Photolabile Compound ofFormula I, II, IVa or IVb where L₂ is other than L¹ is filtered.

The Photolabile Compounds of Formulas I, II, IVa and IVb where L₂ is L¹can be made by allowing about a molar equivalent of M(bdt)₂Cl₂, where Mis Os or Ru and bdt is bipyridine or phenanthroline substituted with anR₁-R₈ group as defined in Formula I, II, IVa or IVb, to react with anexcess amount of an organic molecule in water, ethanol, methanol,isopropyl alcohol, ethylene glycol, acetone, methylene chloride or amixture thereof at reflux under nitrogen. After about 4 to about 8hours, the resultant solution is cooled to room temperature. Theresultant mixture is diluted with water, and to it is added excess NH₄PF₆. The resultant precipitate is filtered, purified via silica-gelchromatography, dried and dissolved in acetone. (n-Bu)₄NH₄ ⁺X, wherein Xis defined in I, II, IVa or IVb, is added to the acetone solution, andthe resultant Photolabile Compound of Formula I, II, IVa or IVb where L₂is L¹ is filtered.

The Photolabile Compounds of Formula III can be made by adding about 2equivalents of a di(C₁-C₁₈ alkyl)glyoxime to CoY₂, wherein Y is OAc, NO₃or Cl, in 1:1 ethanol:water with stirring, wherein the concentration ofCoY₂ in 1:1 ethanol:water ranges from about 10 to about 100 mg/mL. Tothe resultant mixture is added about 1 equivalent of an organic moleculeand about 1 equivalent of L₂ where L¹ is other than L₂, or at leastabout 2 equivalents of the organic molecule where L₂ is L₁. O₂ is thenis bubbled into the solution, resulting in a precipitation of thePhotolabile Compounds of Formula III.

The Photolabile Compounds of Formula V where M² is Fe or Ru can beobtained by dissolving about 1 molar equivalent of (M¹)₃[M²(CN)₅NH₃]2H₂O, where M¹ is defined in Formula V, in about 15 mL ofargon-deoxygenated 1:1 ethanol:water containing about 10 molarequivalents of the organic molecule. The resultant mixture is maintainedat about room temperature under argon for about 1 hour and concentratedin vacuo at about room temperature to a volume of about 1 mL. To theresultant concentrate is added a cold, saturated ethanol solution ofM¹I, resulting in a precipitation of the Photolabile Compounds ofFormula V where M² is Fe or Ru, which are washed with ethanol anddiethyl ether.

The Photolabile Compounds of Formula V where M² is Os can be obtained bydissolving about 1 molar equivalent of (M¹)₃[Os(CN)₅NH₃] 2H₂O, where M¹is defined in Formula V, in about 15 mL of argon-deoxygenated 1:1ethanol:water containing about 10 molar equivalents of the organicmolecule. The resultant mixture is maintained at about 80-90° C. underargon for about 3 h and concentrated in vacuo at about room temperatureto a volume of about 1 mL. The resultant concentrate is purified viachromatography using Sephadex-25 (length, 1.5 m; diameter, 2.5 cm).Fractions containing (M¹)₃[Os(CN)₅L¹]³⁻ are collected and concentratedat about room temperature in vacuo. To the resultant residue is added acold, saturated ethanol solution of M¹I, resulting in a precipitation ofthe Photolabile Compounds of Formula V where M² is Os, which are washedwith ethanol and diethyl ether.

For the present invention, photorelease can generally occur rapidly,e.g., after about 1 microsecond to about 500 or milliseconds followingexposure to visible light of the appropriate wavelength. Suitablewavelengths of light for effective photorelease of an organic moleculefrom a Photolabile Compound range from about 300 to about 500 nm, orfrom about 300 to about 360 nm, or from about 450 to about 500 nm, e.g.,473 nm. Suitable light sources include those which are capable ofirradiating light of the appropriate wavelengths, for example andwithout limitation, commercially available tungsten lamps (Cole-Parmer),arc lamps, xenon continuous lamps, lasers, e.g., blue lasers orphotooptic light sources. Such light sources are commercially available(CrystaLaser, Reno, Nev.; Lasever, Jiangdong, Ningbo, China). Otherforms of light, such as sunlight, infrared light, pulsed infrared light,or UV radiation can also be used for the invention, as necessary ordesired.

Devices and systems suitable for exposing the Photolabile Compounds tolight, particularly visible or infrared light, further include imagingprobes, imaging catheters and fiber optic probes, particularly thosecontaining gradient index, or graded-index, (GRIN) lenses, which aredescribed in U. Utzinger et al., 2003, J. Biomed. Optics, 8(1):121-147;and Fujimoto et al., Photonic Materials, Devices and Systems—LaserMedicine and Medical Imaging Group, RLE Progress Report 144, pp 27-1 to27-35, and which are commercially available. (Sp3 plus, UK). The lightsuitable for exposing the Photolabile Compounds to photorelease anorganic molecule comprises a wavelength of about 300 to about 500 nm, orabout 300 to about 360 nm, or about 450 to about 500 nm. Preferred arevisible or infrared light.

Further in accordance with this invention, the organic molecules canalso be released from the Photolabile Compounds via one-photon ortwo-photon photolysis. Optical memories that utilize a two-photonexcitation are described, for example, by Strickler and Webb, 1991,Optics Letters, 16:1780-1782. A feature of two-photon excitation is theelimination of out-of-focus background. (See, e.g., W. Denk et al.,1990, Science, 248:73-76). Thus, two-photon uncaging can release anorganic molecule only in the plane of focus. (See, e.g., W. Denk et al.,1994, Proc. Natl. Acad. Sci. USA, 91:6629-6633).

In an embodiment, the present invention encompasses a compound ofFormula I, wherein the organic molecule 4-AP. In another embodiment, theinvention encompasses a compound of Formula I, wherein the organicmolecule is TzGly. In another embodiment, the invention encompasses acompound of Formula I, wherein the organic molecule is (tetrazol-5-yl)AMPA. In another embodiment, the invention encompasses a compound ofFormula I, wherein the organic molecule is nicotine or caffeine. Inanother embodiment, the invention encompasses a compound of Formula I,wherein the organic molecule is serotonin, epinephrine, norepinephrine,or dopamine. In another embodiment, the present invention encompasses acompound of Formula I, wherein the organic molecule is adenosine5′-diphosphate ADP, adenosine 5′-triphosphate ATP, adenosine5′-monophosphate AMP, cyclic adenosine 5′-diphosphate ribose, oradenosine 3′,5′-cyclicmonophosphate. In another embodiment, theinvention encompasses a compound of Formula I wherein the organicmolecule is aminobutyric acid or L-glutamic acid, or methyl-D-asparticacid.

In an embodiment, the present invention encompasses a compound ofFormula II, wherein the organic molecule is 4-AP. In another embodiment,the invention encompasses a compound of Formula II, wherein the organicmolecule is TzGly. In another embodiment, the invention encompasses acompound of Formula II, wherein the organic molecule is (tetrazol-5-yl)AMPA. In another embodiment, the invention encompasses a compound ofFormula II, wherein the organic molecule is nicotine or caffeine. Inanother embodiment, the invention encompasses a compound of Formula II,wherein the organic molecule is serotonin, epinephrine, norepinephrine,or dopamine. In another embodiment, the present invention encompasses acompound of Formula II, wherein the organic molecule is adenosine5′-diphosphate ADP, adenosine 5′-triphosphate ATP, adenosine5′-monophosphate AMP, cyclic adenosine 5′-diphosphate ribose, oradenosine 3′,5′-cyclicmonophosphate. In another embodiment, theinvention encompasses a compound of Formula II wherein the organicmolecule is aminobutyric acid or L-glutamic acid, or methyl-D-asparticacid.

In an embodiment, the present invention encompasses a compound ofFormula III, wherein the organic molecule is 4-AP. In anotherembodiment, the invention encompasses a compound of Formula III, whereinthe organic molecule is TzGly. In another embodiment, the inventionencompasses a compound of Formula III, wherein the organic molecule is(tetrazol-5-yl) AMPA. In another embodiment, the invention encompasses acompound of Formula III, wherein the organic molecule is nicotine orcaffeine. In another embodiment, the invention encompasses a compound ofFormula III, wherein the organic molecule is serotonin, epinephrine,norepinephrine, or dopamine. In another embodiment, the presentinvention encompasses a compound of Formula III, wherein the organicmolecule is adenosine 5′-diphosphate ADP, adenosine 5′-triphosphate ATP,adenosine 5′-monophosphate AMP, cyclic adenosine 5′-diphosphate ribose,or adenosine 3′,5′-cyclicmonophosphate. In another embodiment, theinvention encompasses a compound of Formula III wherein the organicmolecule is aminobutyric acid or L-glutamic acid, or methyl-D-asparticacid.

In an embodiment, the present invention encompasses a compound ofFormula IVa or IVb, wherein the organic molecule is 4-AP. In anotherembodiment, the invention encompasses a compound of Formula IVa, whereinthe organic molecule is TzGly. In another embodiment, the inventionencompasses a compound of Formula IVa, wherein the organic molecule is(tetrazol-5-yl) AMPA. In another embodiment, the invention encompasses acompound of Formula IVa, wherein the organic molecule is nicotine orcaffeine. In another embodiment, the invention encompasses a compound ofFormula IVa, wherein the organic molecule is serotonin, epinephrine,norepinephrine, or dopamine. In another embodiment, the presentinvention encompasses a compound of Formula IVa, wherein the organicmolecule is adenosine 5′-diphosphate ADP, adenosine 5′-triphosphate ATP,adenosine 5′-monophosphate AMP, cyclic adenosine 5′-diphosphate ribose,or adenosine 3′,5′-cyclicmonophosphate. In another embodiment, theinvention encompasses a compound of Formula IVa, wherein the organicmolecule is aminobutyric acid or L-glutamic acid, or methyl-D-asparticacid.

In an embodiment, the present invention encompasses a compound ofFormula V, wherein the organic molecule is 4-AP. In another embodiment,the invention encompasses a compound of Formula V, wherein the organicmolecule TzGly. In another embodiment, the invention encompasses acompound of Formula V, wherein the organic molecule is (tetrazol-5-yl)AMPA. In another embodiment, the invention encompasses a compound ofFormula V, wherein the organic molecule is nicotine or caffeine. Inanother embodiment, the invention encompasses a compound of Formula V,wherein the organic molecule is serotonin, epinephrine, norepinephrine,or dopamine. In another embodiment, the present invention encompasses acompound of Formula V, wherein the organic molecule is adenosine5′-diphosphate ADP, adenosine 5′-triphosphate ATP, adenosine5′-monophosphate AMP, cyclic adenosine 5′-diphosphate ribose, oradenosine 3′,5′-cyclicmonophosphate. In another embodiment, theinvention encompasses a compound of Formula V, wherein the organicmolecule is aminobutyric acid or L-glutamic acid, or methyl-D-asparticacid.

In an embodiment, the present invention encompasses a compositioncomprising an effective amount of a Photolabile Compound and aphysiologically acceptable carrier, vehicle, diluent, or excipient.Suitable carriers, vehicles, diluents, or excipients are known to thoseskilled in the art and include, without limitation, physiologicallysterile saline and others as described herein.

In another embodiment, the composition comprises two or more PhotolabileCompounds, each having a different metal, M.

In another embodiment, the present invention provides a vesselcontaining a Photolabile Compound. The vessel can further contain abiological sample, wherein the sample is, for example, hair, an organspecimen; a tissue or cell, for example, a neuronal tissue or cell; atumor or cancer or neoplastic tissue or cell; or a tissue or cellremoved from a patient or subject of interest. Tissue specimens slicedfrom microtomes, for example, are examples of suitable biologicalsamples.

Any type of vessel that is capable of transmitting the wavelengths oflight used for releasing the organic molecules comprising thePhotolabile Compounds, and that is inert to solvent in which aPhotolabile Compound is suspended, is suitable for use. For example, thevessel can be made of glass, plastic, acrylic, quartz, a noble metal,etc. In addition, if the vessel is composed of, or encased in, metal,e.g., aluminum, titanium, or stainless steel, exposure to light isperformed through the top of the vessel, or through a “window” or otherlight-penetrable opening in the vessel. For solid-like materials,acrylic plastic or acrylamide-bisacrylamide gel, etc., for example, canbe used as media in which the Photolabile Compounds are contained. Forexample, an acrylic plastic coating formulated using a CHCl₃ solution ofacrylic and a Ru(bpy) complex changed its spectrum followingirradiation, thus allowing photorelease in a solid state. For such solidstate aspects of the invention, the temperature may be kept at 4K.

Solvents suitable in which a Photolabile Compounds can be exposed tolight include aqueous solvents; water; acetonitrile; alcohol, e.g.,methanol, ethanol; acetone; chlorinated solvents such as CH₂Cl₂ andCHCl₃; or dimethylsulfoxide.

Suitable temperatures at which a Photolabile Compound is exposed tolight range, in general, from about 0° C. to about 100-150° C.

In another embodiment, this invention encompasses a method for releasingan organic molecule from a Photolabile Compound. The method comprisesexposing a Photolabile Compound to light under conditions sufficient torelease the organic molecule from the compound. In the method, the lightcomprises a wavelength of about 300 to about 500 nm, or about 300 toabout 360 nm, or about 450 to about 500 nm. Further, the exposing canoccur at a temperature from about 0° C. to about 150° C. In anembodiment, the methods of the invention comprise a PhotolabileCompound, e.g., a compound of Formula I-IVb, light of a wavelength ofabout 300 nm to about 500 nm; L¹ being L², and a temperature of about 0°C. to about 150° C. In another embodiment, the methods comprise aPhotolabile Compound, light of a wavelength of about 300 nm to about 360nm; L¹ being L², and a temperature of about 0° C. to about 150° C. Inanother embodiment, the methods comprise a Photolabile Compound, lightof a wavelength of about 450 nm to about 500 nm; L¹ being L², and atemperature of about 0° C. to about 150° C. In another embodiment, themethods comprise a Photolabile Compound, visible or infrared light; L¹being L², and a temperature of about 0° C. to about 150° C. In anotherembodiment, the methods comprise a Photolabile Compound of Formula V,light of a wavelength of about 300 nm to about 500 nm and a temperatureof about 0° C. to about 150° C. In another embodiment, the methodscomprise a compound of Formula V, light of a wavelength of about 300 nmto about 360 nm and a temperature of about 0° C. to about 150° C. Inanother embodiment, the methods comprise a compound of Formula V, lightof a wavelength of about 450 nm to about 500 nm and a temperature ofabout 0° C. to about 150° C. In another embodiment, the methods comprisea compound of Formula V, visible or infrared light and a temperature ofabout 0° C. to about 150° C.

In another embodiment, the present invention embraces a method ofprotecting an organic molecule from an effect of an enzyme, comprisingallowing the organic molecule and a compound of Formula I′:

wherein m is 2, and R¹-R⁸, the organic molecule, and X are as describedfor Formula I, to react under conditions sufficient to make a compoundof Formula I.

Protection from an enzyme means that an organic molecule is concealed ormasked from being acted upon by an enzyme, e.g., cleaved or modified, byan enzyme, prior to exposure of the Photolabile Compound to light.

In another embodiment, the present invention embraces a method ofprotecting an organic molecule from an effect of an enzyme. comprisingallowing the organic molecule and a compound of Formula II′:

wherein m is 2, and R¹-R⁸, the organic molecule, and X are as describedfor Formula II, to react under conditions sufficient to make a compoundof Formula II.

In another embodiment, the present invention embraces a method ofprotecting an organic molecule from an effect of an enzyme, comprisingallowing the organic molecule and a compound of Formula III′:

wherein m is 3, and R¹-R⁴, the organic molecule, and X as are describedfor Formula III, to react under conditions sufficient to make a compoundof Formula III.

In another embodiment, the present invention embraces a method ofprotecting an organic molecule from an effect of an enzyme, comprisingallowing the organic molecule and a compound of Formula IVa′:

wherein m is 2 and R¹-R⁸, the organic molecule, and X are as describedfor Formula IVa, to react under conditions sufficient to make a compoundof Formula IVa.

In another embodiment, the present invention embraces a method ofprotecting an organic molecule from an effect of an enzyme, comprisingallowing the organic molecule and a compound of Formula IVb′:

wherein m is 2 and R¹-R⁸, the organic molecule, and X are as describedfor Formula IVb, to react under conditions sufficient to make a compoundof Formula IVb.

In yet another embodiment, the present invention embraces a method ofprotecting an organic molecule from an effect of an enzyme, comprisingallowing the organic molecule and a compound of Formula V′:

wherein M¹ is Li⁺, Na⁺, or K⁺; and M² is Fe, Ru, or Os, to react underconditions sufficient to make a compound of Formula V.

In an embodiment, the invention encompasses a method for assaying anorganic molecule, comprising exposing a Photolabile Compound and abiological sample to light under conditions sufficient to release theorganic molecule from the Photolabile Compound, and (b) determining aneffect of the organic molecule on the biological sample. The sample canbe a biological sample, such as a sample excised, removed, or otherwisetaken from a subject's body. The subject's biological sample can be, forexample, a hair sample, an organ or tissue sample, e.g., from a biopsyor an autopsy, or a cell sample. In addition, the biological sample canbe a body fluid sample. Body fluid samples include, without limitation,blood, serum, plasma, lymph, saliva, sputum, tears, semen, or urine.Biological samples can further include, without limitation, braintissue, brain cells, muscle tissue, muscle cells, muscle fibers,fibroblasts, tissue slices, or fine tissue specimens, from any organ ofthe body, sarcoplasmic reticulum, skin tissue, membrane preparations orfragments, etc.

The light for exposing the compounds according to the methods of thisinvention can be sunlight, photo-optic light, or laser light.Advantageously, in the methods of this invention, the light for exposingthe compound is other than UV radiation. Thus, for example, the lightcan be visible light or infrared light, including one-photon andtwo-photon light. The light can be emitted from a variety of sources,including without limitation, a laser light source, a tungsten lightsource, a photooptic light source, etc. Another advantage of visiblelight to expose or irradiate the compounds of the invention relates tothe convenience and ability to use a visible light microscope, forexample, to view a sample into which a compound is introduced and tomicroscopically visualize or monitor a photoreleased ligand from thecompound after exposure to visible light. Because many microscopes donot transmit UV light, it is advantageous to be able to use a non-quartzmicroscope in accordance with this invention. Yet another advantage tothe use of visible light is that it is not detrimental to living cellsand tissues, making it beneficial for in vivo patient use. In addition,for patient use, the light can be specifically directed to an area wherea Photolabile Compound is introduced or administered by the use of lasertechnology, fibers, probes, tubes, and the like. Such probes, fibers, ortubes can be directly inserted, for example, into a body cavity oropening, or under or through the skin, to expose the PhotolabileCompound to light.

In another of its embodiments, the present invention embraces a methodof making an organic molecule bioavailable to a subject. The organicmolecule can be made bioavailable to a localized body region or area ofthe subject, or systemically to the whole body. Local bioavailability ofthe Photolabile Compounds is achieved, for example, via delivery devicesand methods that allow the compounds to be directly administered, forexample, inserted into a body cavity, or opening, or through or into theskin. The method of this embodiment involves administering a PhotolabileCompound to the subject, and exposing the compound to light underconditions sufficient to release the organic molecule from the compound,thereby making the organic molecule bioavailable to the subject, and/orto a body site or region of the subject. The exposure to light cancomprise the use of probes, fibers, tubes, and the like, which allow thelight to be specifically directed to the area of interest on or withinthe body. Alternatively, the Photolabile Compounds can be administeredto the patient kept in the dark; for photorelease of the organicmolecule, the patient can be moved to the light where exposure to lightand photorelease occur. In an embodiment according to this method, theorganic molecule has:

(a) a 5-membered monocyclic aromatic ring, one of the ring's membersbeing a nitrogen atom that forms a bond with a metal, M;

(b) a 6-membered monocyclic aromatic ring, one of the ring's membersbeing a nitrogen atom that forms a bond with a metal. M;

(c) an 8-10-membered bicyclic ring, one of the bicyclic rings beingaromatic and having a nitrogen atom member that forms a bond with ametal. M;

(d) an —NH₂ group whose nitrogen atom forms a bond with the metal; or

(e) a —COOH group, one of whose oxygen atoms forms a bond with a metal,M.

In another embodiment, the organic molecule has:

(a) a tetrazolyl group, one of its nitrogen atoms forming a bond withRu;

(b) nicotine or caffeine, whose pyridyl nitrogen atom forms a bond withRu;

(c) an 8-10-membered bicyclic ring, one of the bicyclic rings beingaromatic and having a nitrogen atom member that forms a bond with Ru;

(d) an —NH₂ group whose nitrogen atom forms a bond with Ru; or

(e) a —COOH group, one of whose oxygen atoms forms a bond with Ru.

In a related embodiment, the Photolabile Compounds are useful forreleasing an organic molecule, such as a drug, pharmaceutical, smallbiologically active molecule, and the like as described above. Releaseof the organic molecule from the Photolabile Compound allows the organicmolecule to become bioavailable to a subject, or patient, afflicted witha disease, disorder, pathology, or condition. The Photolabile Compoundsand organic molecules are useful in veterinary and human medicine.Diseases, disorders, pathologies, or conditions for which making anorganic molecule bioavailable would serve to treat, ameliorate, reduce,eliminate, abate, or prevent the disease, disorder, pathology, orcondition are further described below and include, as nonlimitingexamples, peripheral and central nervous system disorders, neurologicaldisorders and disorders related thereto, neurodegenerative disorders anddisorders related thereto, epilepsy, seizures, migraines, headaches,stroke, anxiety, depression, restricted brain function, addictivedisorders, neuroses, psychoses, pruritic conditions, Parkinson'sdisease, Huntington's chorea, cognitive disorders, memory lapses,Alzheimer's disease, dementia, dyskinesia, muscle spasms, retinopathy,vomiting, cancers, neoplasms, tumors, vascular diseases, andcardiovascular diseases.

As further, yet non-limiting examples, the organic molecule is aneurochemical that blocks potassium channels for use, for example, intreating neurodegenerative, or neurological diseases or disorders. In aparticular embodiment, the organic molecule is 4-AP, which is a calciumchannel blocker. In another embodiment, the organic molecule is TzGly,which is an NMDA-receptor agonist that is more potent than NMDA. In oneembodiment, for making an organic molecule of the invention bioavailableto a subject in need thereof, the exposure of the Photolabile Compoundto light can occur at the site of the disease, disorder, pathology, orcondition, such as a site of a tumor, neoplasm, or cancer lesion orgrowth, thereby releasing the organic molecule locally and moreprecisely at the needed location.

In other related embodiments, the present invention provides methods fortreatment, therapy, and prophylaxis by administering an effective amountof a Photolabile Compound, or a physiologically acceptable compositioncomprising a Photolabile Compound to a subject, so as to make an organicmolecule bioavailable to the subject. The Photolabile Compound can besubstantially purified (e.g., substantially free from substances thatlimit its effect or produce undesired side-effects). Advantageously, formethods in which a Photolabile Compound is administered to a subject,the light, e.g., infrared, laser, or visible light, for photoreleasingthe organic molecule to make it bioavailable to the subject can bedirected to an internal site or region of interest by using photoopticdevices, probes and fibers, such as are known in the art and describedsupra. Those having skill in the art can employ, manipulate, andinternally direct the devices for exposing a Photolabile Compound tolight after the Photolabile Compound is administered to a subject.

In the methods of the present invention involving subjects, and/or thetreatment, therapy, or prophylaxis of a disease, disorder, pathology, orcondition, the subject is preferably an animal, including but notlimited to, mammals such as human and non-human primates, cows, pigs,horses, goats, sheep, rabbits, chickens, cats, dogs, guinea pigs, rats,mice, etc. The methods of the invention especially encompass humantreatments.

Various delivery systems are known and can be used to administer aPhotolabile Compound, e.g., in sterile solution, encapsulation inliposomes, microparticles, microcapsules, or receptor-mediatedendocytosis (See, e.g., Wu and Wu, 1987, J. Biol. Chem., 262:4429-4432).Methods of introduction include, but are not limited to, intradermal,intramuscular, intraperitoneal, intravenous, subcutaneous, intranasal,epidural, topical, transdermal, parenteral, intrathecal, vaginal,rectal, colorectal, oral, intracranial, retroorbital, intrasternalroutes, or a combination thereof.

The Photolabile Compounds or compositions may be administered by anyconvenient route or mode, for example, by continuous infusion,non-continuous infusion, or bolus injection, by absorption throughepithelial or mucocutaneous linings (e.g., oral mucosa, epidermis,rectal and intestinal mucosa, etc.) and may be administered togetherwith other biologically active and/or therapeutic agents. Administrationcan be systemic or local. In addition, it may be desirable to introducethe Photolabile Compounds or compositions into the central nervoussystem by any suitable route, including intraventricular and intrathecalinjection; intraventricular injection may be facilitated by anintraventricular catheter, for example, attached to a reservoir, such asan Ommaya reservoir. Pulmonary administration can also be employed,e.g., by use of an inhaler or nebulizer, and formulation with anaerosolizing agent.

In a particular embodiment, it may be desirable to administer thePhotolabile Compounds or compositions locally to the area in need oftreatment. This may be achieved, for example, by local infusion duringsurgery, topical application, e.g., in conjunction with a wound dressingafter surgery, by injection, by means of a catheter, by means of asuppository, or by means of an implant, where the implant is a porous,non-porous, or gelatinous material, including membranes, such assialastic membranes, or fibers.

In another embodiment involving topical administration, a transdermalpatch can be used. In accordance with this embodiment, the PhotolabileCompound remains unexposed to light until the patch is manipulated by apatient or medical provider so that all or a portion of the patchcontaining a Photolabile Compound is exposed to light. Accordingly, thepatch can be opened and the bioactive molecule released, or “activated”from the compound after exposure to light, for example, by the patient'smoving from a dark room to a lighted room, or from a dark area to alight area; by the patient's directly exposing the patch, or a portionthereof, to a suitable light source, or by the patient's exposing all ora portion of the patch to daylight. A variety of types of transdermalpatches are known and used by the skilled practitioner in the art.Alternatively for topical administration, a Photolabile Compound can beformulated into a light-sensitive composition, which is contained in adark, light-protected container, and applied topically to the area ofinterest, e.g., applied to or rubbed onto the skin of a subject, in thedark. Following topical application in the dark, the area of interest isexposed to light, or to an appropriate light source, or the subjectmoves into the light, thereby causing the organic molecule of thePhotolabile Compound to be released.

In another embodiment, the Photolabile Compounds or compositions can bedelivered in a vesicle, in particular a liposome (See, e.g., Langer,1990, Science, 249:1527-1533; Treat et al., In: Liposomes in the Therapyof Infectious Disease and Cancer, Lopez-Berestein and Fidler (eds.),Liss, New York, pp. 353-365 (1989); Lopez-Berestein, ibid., pp. 317-327;see generally ibid.) In yet another embodiment, the PhotolabileCompounds or compositions can be delivered in a controlled-releasesystem. For example, a pump may be used (see Langer, supra; Sefton,1987, CRC Crit. Ref. Biomed. Eng. 14:201; Buchwald et al., 1980,Surgery, 88:507; Saudek et al., 1989, NEJM, Med. 321:574 (1989)), orpolymeric materials can be used (See, e.g., Medical Applications ofControlled Release, Langer and Wise (eds.), CRC Press, Boca Raton, Fla.(1974); Controlled Drug Bioavailability, Drug Product Design andPerformance, Smolen and Ball (eds.), Wiley, New York (1984); Ranger andPeppas, 1983, J. Macromol. Sci. Rev. Macromol. Chem., 23:61; Levy etal., 1985, Science, 228:190; During et al., 1989, Neurol., 25:351; andHoward et al., 1989, J. Neurosurg., 71:105). Moreover, acontrolled-release system can be placed proximal to the therapeutictarget, e.g., the brain, thus requiring only a fraction of the systemicdose (see, e.g., Goodson, 1984, In: Medical Applications of ControlledRelease, Vol. 2, pp. 115-138). As further guidance, other controlledrelease systems are found in Langer, 1990, Science, 249:1527-1533.

The Photolabile Compounds are also provided in effective amounts inpharmaceutical compositions comprising a pharmaceutically acceptablecarrier, diluent, excipient, or vehicle, for example, for use astherapeutics. In one embodiment, the term “pharmaceutically acceptable”refers to approval by a regulatory agency of the Federal or a stategovernment, or listed in the U.S. Pharmacopeia or other generallyrecognized pharmacopeia for use in animals, and more particularly, inhumans. The terms vehicle, carrier, or excipient refer to a diluent oradjuvant in or with which the therapeutic is administered. Suchpharmaceutical carriers, vehicles, or excipients can be sterile liquids,such as water and oils, including those of petroleum, animal, vegetableor synthetic origin, e.g., peanut oil, soybean oil, mineral oil, sesameoil and the like. Water is a preferred carrier when a pharmaceuticalcomposition is administered intravenously and is water soluble. Salinesolutions and aqueous dextrose and glycerol solutions can also beemployed as liquid carriers, particularly for injectable solutions.Suitable pharmaceutical excipients include starch, glucose, lactose,sucrose, gelatin, malt, rice, flour, chalk, silica gel, sodium stearate,glycerol monostearate, talc, sodium chloride, dried skim milk, glycerol,propylene, glycol, water, ethanol and the like. If needed or desired,the composition of the invention can also contain minor amounts ofwetting or emulsifying agents, or pH buffering agents.

The Photolabile Compounds and compositions of the present invention canbe formulated as solutions, suspensions, emulsions, tablets, pills,capsules, powders, sustained-release formulations and the like. Thecompositions can be formulated as a suppository, with traditionalbinders and carriers such as triglycerides. Oral formulations caninclude standard carriers, such as pharmaceutical grades of mannitol,lactose, starch, magnesium stearate, sodium saccharine, cellulose,magnesium carbonate, etc. Examples of suitable pharmaceutical carriersand the like are described in the current edition of “Remington'sPharmaceutical Sciences” by E. W. Martin. Such compositions routinelycontain a therapeutically effective amount of the Photolabile Compound,preferably in purified form, together with a suitable amount of carrierso as to provide the form for proper administration to a subject. Theformulation should suit the mode of administration.

In another embodiment, a Photolabile Compound of the invention isformulated in accordance with routine procedures as a pharmaceuticalcomposition adapted for intravenous administration to human beings.Typically, compositions for intravenous administration are solutions insterile isotonic aqueous buffer. Where necessary, the composition mayalso include a solubilizing agent and a local anesthetic such aslidocaine to ease pain at the site of the injection. Generally, theingredients are supplied either separately or mixed together in unitdosage form, for example, as a dry lyophilized powder or water freeconcentrate in a hermetically sealed container, such as an ampoule orsachette indicating the quantity of active agent. Where the compositionis to be administered by infusion, it can be dispensed with an infusionbottle containing sterile pharmaceutical grade water or saline. Wherethe composition is administered by injection, an ampoule of sterilewater for injection or saline can be provided so that the ingredientsmay be mixed prior to administration. Sterility for of a composition fortherapeutic administration is readily accomplished by filtration throughsterile filtration membranes (e.g., 0.2 micron membranes). Therapeuticsgenerally are placed into a container having a sterile access port, forexample, an intravenous solution bag or vial having a stopper pierceableby a hypodermic injection needle. Therapeutics are typically stored inunit or multi-dose containers, for example, sealed ampoules or vials, asan aqueous solution or as a lyophilized formulation for reconstitution.Where necessary, the ampoule or vial is essentially impenetrable bylight. As an example of a lyophilized therapeutic formulation, 10-mlvials are filled with 5 ml of sterile-filtered 1% (w/v) aqueoustherapeutic solution, and the resulting mixture is lyophilized. Theinfusion solution is prepared by reconstituting the lyophilizedtherapeutic using bacteriostatic Water-for-Injection.

The amount of a Photolabile Compound which will be effective in thetreatment, amelioration, reduction, elimination, inhibition, orprevention of a particular disease, condition, pathology, or disorderassociated with the use and bioactivity of an organic molecule can bedetermined by standard clinical techniques. An “effective amount” or a“pharmaceutically effective amount” of a Photolabile Compound of thisinvention refers to an amount effective for treating, ameliorating,reducing, abating, eliminating, preventing, a disease, condition,pathology, or disorder for which the compound is being used. Inparticular embodiments, an effective amount is an amount effective formaking an organic molecule of the invention bioavailable to a subject.If another therapeutic agent is used in conjunction with the PhotolabileCompounds, the effective amount of the therapeutic agent refers to anamount effective for providing the therapeutic effect of the therapeuticagent. The precise dose to be employed in the formulation will alsodepend on the route of administration, as well as an individualpatient's circumstances, such as age, health and vital statistics of thepatient, and the severity of the disease, condition, or disorder. Dosingshould be decided according to the judgment of the medical practitionerbased on an evaluation of the patient and considerations of a patient'sphysiologic situation and medical history. In addition, in vitro assaysmay optionally be used to assist in determining optimal dosage ranges.Effective doses can be extrapolated from dose-response curves derivedfrom in vitro or in vivo animal model test systems.

As general guidance, the total effective amount of a PhotolabileCompound administered parenterally per dose will be in the range ofabout 1 μg/kg/day to 10 mg/kg/day of a subject's body weight, although,as noted above, this will be subject to discretion based on thesubject's condition and the above-mentioned variables. A therapeuticdose can also be at least 0.01 mg/kg/day, or between about 0.01 and 1mg/kg/day, with particular regard for human administration. If givencontinuously, a therapeutic is typically administered at a dose rate ofabout 1 μg/kg/hour to about 50 μg/kg/hour, either by 1 to 4 injectionsper day or by continuous subcutaneous infusions, e.g., using amini-pump. An intravenous bag solution may also be employed. The lengthof treatment needed to observe changes and the interval followingtreatment for responses to occur will likely vary depending on thedesired effect. In some embodiments, suitable effective dosage amountsrange from about 10 μg to about 2500 mg about every 4 hours, althoughthe amounts are typically about 100 mg or less. In one embodiment, theeffective dosage of a Photolabile Compound ranges from about 0.01 mg toabout 100 mg about every 4 hours. In another embodiment, the effectivedosage of a compound of the invention ranges from about 0.020 mg toabout 50 mg every 4 hours, and in another embodiment, about 0.025 mg toabout 20 mg about every 4 hours. The effective dosage amounts refer tototal amounts administered. Thus, if more than one of the PhotolabileCompounds is administered, the effective dosage amounts correspond tothe total amount administered.

In another embodiment, if a Photolabile Compound is contacted with abiological sample in vitro, an effective amount will typically rangefrom about 0.01 μg/L to about 5 mg/L; in another embodiment from about0.01 μg/L to about 2.5 mg/L; in another embodiment, from about 0.01 μg/Lto about 0.5 mg/L; and in yet another embodiment, from about 0.01 μg/Lto about 0.25 mg/L of a solution or suspension of a pharmaceuticallyacceptable carrier, diluent, or excipient. In an embodiment, the volumeof solution or suspension is from about 1 μL to about 1 mL; in anotherembodiment, the volume of solution or suspension is about 200 μL.

Examples of neoplastic or hyperproliferative diseases, disorders,pathologies, or conditions that can be treated, ameliorated, reduced,abated, eliminated, inhibited, prevented, and/or diagnosed using thePhotolabile Compounds and photoreleased organic molecules include, butare not limited to, neoplasms (cancers or tumors) located in the colon,abdomen, bone, breast, digestive system, esophagus, liver, pancreas,peritoneum, endocrine glands (adrenal, parathyroid, pituitary,testicles, ovaries, cervix, thymus, thyroid), eye, head and neck,nervous (central and peripheral), lymphatic system, pelvis, skin, softtissue, spleen, thoracic areas, bladder, and urogenital system. Cancersthat may be treatable using the Photolabile Compounds include follicularlymphomas, carcinomas with p53 mutations, and hormone-dependent tumors,including, but not limited to colon cancer, cardiac tumors, pancreaticcancer, melanoma, retinoblastoma, glioblastoma, lung cancer, intestinalcancer, testicular cancer, stomach cancer, neuroblastoma, myxoma, myoma,lymphoma, endothelioma, osteoblastoma, osteoclastoma, osteosarcoma,chondrosarcoma, adenoma, breast cancer, prostate cancer, Kaposi'ssarcoma and ovarian cancer, or metastases thereof. Autoimmune diseases,disorders, or conditions may be treatable with the Photolabile Compoundsand include multiple sclerosis, Sjogren's syndrome, Hashimoto'sthyroiditis, biliary cirrhosis, Bechet's disease, Crohn's disease,polymyositis, systemic lupus erythematosus and immune-relatedglomerulonephritis, rheumatoid arthritis, ischemic injury (e.g., causedby myocardial infarction, stroke and reperfusion injury), liver injury(e.g., hepatitis related liver injury, ischemia/reperfusion injury,cholestosis (bile duct injury) and liver cancer); toxin-induced liverdisease (e.g., caused by alcohol), septic shock, cachexia and anorexia.Viral infections (such as herpes viruses, pox viruses and adenoviruses),inflammation, graft versus host (GVH) disease, acute graft rejection,and chronic graft rejection may also be treatable with the PhotolabileCompounds.

Additional diseases or conditions associated with abnormal and increasedcell survival that may be treated, ameliorated, reduced, abated,eliminated, inhibited, prevented, and/or diagnosed using the PhotolabileCompounds include, but are not limited to, progression and/or metastasesof malignancies and related disorders such as leukemia (including acuteleukemias (e.g., acute lymphocytic leukemia, acute myelocytic leukemia,including myeloblastic, promyelocytic, myelomonocytic, monocytic, anderythroleukemia) and chronic leukemias (e.g., chronic myelocytic(granulocytic) leukemia and chronic lymphocytic leukemia)), polycythemiavera, lymphomas (e.g., Hodgkin's disease and non-Hodgkin's disease),multiple myeloma, Waldenstrom's macroglobulinemia, heavy chain disease,and solid tumors including, but not limited to, sarcomas and carcinomassuch as fibrosarcoma, myxosarcoma, liposarcoma, chondrosarcoma,osteogenic sarcoma, chordoma, angiosarcoma, endotheliosarcoma,lymphangiosarcoma, lymphangioendotheliosarcoma, synovioma, mesothelioma,Ewing's tumor, leiomyosarcoma, rhabdomyosarcoma, colon carcinoma,pancreatic cancer, breast cancer, ovarian cancer, prostate cancer,squamous cell carcinoma, basal cell carcinoma, adenocarcinoma, sweatgland carcinoma, sebaceous gland carcinoma, papillary carcinoma,papillary adenocarcinomas, cystadenocarcinoma, medullary carcinoma,bronchogenic carcinoma, renal cell carcinoma, hepatoma, bile ductcarcinoma, choriocarcinoma, seminoma, embryonal carcinoma, Wilm's tumor,cervical cancer, testicular tumor, lung carcinoma, small cell lungcarcinoma, bladder carcinoma, epithelial carcinoma, glioma, astrocytoma,medulloblastoma, craniopharyngioma, ependymoma, pinealoma,hemangioblastoma, acoustic neuroma, oligodendroglioma, menangioma,melanoma, neuroblastoma, and retinoblastoma.

In another embodiment, the Photolabile Compounds may be needed astherapeutics to stimulate epithelial cell proliferation and basalkeratinocytes for the purpose of wound healing, and to stimulate hairfollicle production and the healing of dermal wounds. The PhotolabileCompounds of the invention may be clinically useful in stimulating woundhealing, including surgical wounds, excisional wounds, deep woundsinvolving damage of the dermis and epidermis, eye tissue wounds, dentaltissue wounds, oral cavity wounds, diabetic ulcers, dermal ulcers,cubitus ulcers, arterial ulcers, venous stasis ulcers, burns resultingfrom heat exposure or chemicals, and other abnormal wound healingconditions such as uremia, malnutrition, vitamin deficiencies andcomplications associated with systemic treatment using steroids,radiation therapy, anti-neoplastic drugs and anti-metabolites.

Other diseases, disorders, or conditions that may be treated,ameliorated, reduced, abated, eliminated, inhibited, prevented, and/ordiagnosed with the Photolabile Compounds include AIDS; neurodegenerativediseases, disorders, and/or conditions (such as Alzheimer's disease,Parkinson's disease, amyotrophic lateral sclerosis (ALS), multiplesclerosis, Retinitis pigmentosa (RP), cerebellar degeneration and braintumor or prior associated disease).

In one embodiment, diseases and conditions that are treatable usingcalcium channel blockers, e.g., 4AP, include without limitation, heartdisease, hypertension, angina, chest pain, cardiovascular diseases, suchas coronary artery disease, cardiomyopathies, valvular heart disease,renal disease, Peyronie's disease and neurological, neurophysiological,or neuromuscular diseases and conditions, e.g., amyotrophic lateralsclerosis (ALS), multiple sclerosis.

In another embodiment, diseases that are treatable using NMDA receptoragonists or antagonists, e.g., TzGly, include without limitation,neurological, neurodegenerative, or neurophysiological diseases,disorders, and conditions, such as Alzheimer's disease, Parkinson'sdisease, Huntington's disease, and dyskinesias. In another embodiment,neurological, neurodegenerative, and neurophysiological diseases, e.g.,Parkinson's disease, Alzheimer's disease, etc., are treatable usingTz-AMPA.

In another embodiment, the present invention relates to kits comprisinga Photolabile Compound and instructions for use. A kit may be used in adiagnostic, screening, or testing assay. A kit may also be apharmaceutical pack, particularly for use in treating or preventing adisease, disorder, pathology, or condition. A kit for pharmaceutical useis typically sterile and contains a Photolabile Compound in an amounteffective to treat or prevent a disease, disorder, pathology, orcondition, and a pharmaceutically acceptable carrier, diluent, orexcipient. The kit, or a pharmaceutical pack, can comprise one or morevessels or containers filled with an effective amount, e.g., unit dosageform, of one or more of the Photolabile Compounds or compositions of theinvention, and a pharmaceutically acceptable carrier, diluent, orexcipient. The kit, or pharmaceutical pack, can further comprise alabel. In addition, the kit, or pharmaceutical pack, can also include aunit dosage form of another therapeutic agent, for example, a containercontaining an effective amount of the other therapeutic agent. The kit,or pharmaceutical pack, may further optionally contain a notice in theform prescribed by a governmental agency regulating the manufacture,use, or sale of pharmaceuticals or biological products, reflectingapproval by the agency of manufacture, use or sale for humanadministration. The kit, or pharmaceutical pack, can also contain adevice useful for administering the unit dosage forms. Examples of suchdevices include, without limitation, a syringe, a drip bag, a patch, aninhaler, and an enema bag or container.

EXAMPLES

The examples described below are provided to illustrate the presentinvention and are not included for the purpose of limiting theinvention.

Example 1

Synthesis of [Ru(bpy)₂(4AP)₂]Cl₂. 159 mg of Ru(bpy)₂Cl₂, where bpy2,2′-bipyridine, were suspended in 7 mL of water at 85° C. under N₂.After dissolution, 66 mg of 4-aminopyridine (“4AP”) were added, and theresultant solution was heated for about 20 minutes at about 50-80° C. orgreater. A molar excess of NH₄ PF₆, was added, and the resultant redsolid was washed with water and dried. The red solid was dissolved in aminimal amount of acetone, and to the acetone solution was addedtetraethylammonium chloride, precipitating [Ru(bpy)₂(4AP)₂]Cl₂ (79%yield).

Example 2

Synthesis of [Ru(bpy)₂(TzGly)₂]Cl₂. [Ru(bpy)₂(TzGly)₂]Cl₂ was madeaccording to the procedure used to make [Ru(bpy)₂(4AP)₂]Cl₂ set forth inExample 1, except that (RS)-(tetrazol-5-yl)glycine (“TzGly”) was used inplace of 4AP.

Example 3

Synthesis of [Ru(bpy)₂(5HT)₂]Cl₂. [Ru(bpy)₂(5HT)₂]Cl₂ is made accordingto the procedure used to make [Ru(bpy)₂(4AP)₂]Cl₂ set forth in Example1, except that serotonin (“5HT”) is used in place of 4AP.

Example 4

Synthesis of [Ru(bpy)₂(4AP)(PPh₃)]Cl₂. Ru(bpy)₂Cl₂, wherebpy=2,2′-bipyridine, was suspended in water at a concentration of 10mg/mL at 85° C. under N₂. After dissolution, 1 equivalent of PPh₃ wasadded, and the resultant solution was heated for about 60 minutes atabout 50-80° C. or greater. 1.1 Equivalents of 4AP were subsequentlyadded, and heating continued for an additional 30 minutes. A molarexcess of NH₄ PF₆, was added, and the resultant orange solid was washedwith water and dried. The orange was dissolved in a minimal amount ofacetone, and to the acetone solution was added tetraethylammoniumchloride, precipitating [Ru(bpy)₂(4AP)(PPh₃)]Cl₂.

Example 5

Synthesis of [Ru(bpy)₂(TzGly)(PPh₃)]Cl₂. [Ru(bpy)₂(TzGly)(PPh₃)]Cl₂ wasmade according to the procedure used to make [Ru(bpy)₂(4AP)(PPh₃)]Cl₂set forth in Example 4, except that TzGly was used in place of 4AP.

Example 6

Synthesis of [Ru(bpy)₂(5HT)(PPh₃)]Cl₂. [Ru(bpy)₂(5HT)(PPh₃)]Cl₂ is madeaccording to the procedure used to make [Ru(bpy)₂(4AP)(PPh₃)]Cl₂ setforth in Example 4, except that serotonin is used in place of 4AP.

Example 7

Synthesis of [Ru(bpy)₂(nicotine)(PPh₃)]Cl₂.[Ru(bpy)₂(nicotine)(PPh₃)]Cl₂ is made according to the procedure used tomake [Ru(bpy)₂(4AP)(PPh₃)]Cl₂ set forth in Example 4, except thatnicotine is used in place of 4AP.

Example 8

Synthesis of [Ru(bpy)₂(TzGly)(py)]Cl₂. [Ru(bpy)₂(TzGly)(py)]Cl₂, wherepy=pyridine, was made according to the procedure used to make[Ru(bpy)₂(4AP)(PPh₃)]Cl₂ set forth in Example 4, except that TzGly wasused in place of 4AP and pyridine was used in place of PPh₃.

Example 9

Synthesis of [Ru(bpy)₂(4AP)(py)]Cl₂. [Ru(bpy)₂(4AP)(Py)]Cl₂, wherepy=pyridine, is made according to the procedure used to make[Ru(bpy)₂(4AP)(PPh₃)]Cl₂ set forth in Example 4, except that pyridine isused in place of PPh₃.

Example 10

Synthesis of [Ru(bpy)₂(5HT)(py)]Cl₂. [Ru(bpy)₂(5HT)(py)]Cl₂, wherepy=pyridine, is made according to the procedure used to make[Ru(bpy)₂(4AP)(PPh₃)]Cl₂ set forth in Example 4, except that 5HT is usedin place of 4AP and pyridine is used in place of PPh₃.

Example 11

Synthesis of [Ru(bpy)₂(nicotine)(py)]Cl₂. [Ru(bpy)₂(nicotine)(py)]Cl₂,where py=pyridine, is made according to the procedure used to make[Ru(bpy)₂(4AP)(PPh₃)]Cl₂ set forth in Example 4, except that nicotine isused in place of 4AP and pyridine is used in place of PPh₃.

Example 12

Synthesis of Co(DMG)₂(5HT)(Cl). CoCl₂ was dissolved in a 1:1 v/v mixtureof water/ethanol at a final concentration of about 0.2 M. Twoequivalents of dimethylglyoxime (“DMG”) were added, and the resultantmixture was allowed to stir under N₂ until dissolution. One equivalentof 5HT was added, air was bubbled into the resultant mixture for 6 hoursand Co(DMG)₂(5HT)(Cl) precipitated. The precipitated product wasfiltered and washed.

Example 13

Photorelease of 4AP from [Ru(bpy)₂(4AP)₂]Cl₂. UV-vis spectra in waterwere obtained with an HP 8453 diode array spectrophotometer. RMN ¹Hspectra were obtained using a Bruker 500 MHz equipment. CV measurementswere performed with a PAR 273A potentiostat. Irradiation was effected bymeans of a pulsed Xe lamp, (pulse energy ˜0.5 J), with a low-pass filterat 480 nm. Irradiation using a 473 nm DPSS laser gave similar results.

[Ru(bpy)₂(4AP)₂]Cl₂ is very soluble in water and stable in the dark,while undergoing decomposition under irradiation with visible light inits metal-to-ligand charge transfer (MLCT) band, centered at 489 nm. (InCH₃CN solution, the absorption band is red-shifted to 492 nm, consistentwith the lower polarity of the solvent, despite a previouscharacterization that reported 450 nm. However, light exposure of aCH₃CN solution of [Ru(bpy)₂(4AP)₂]Cl₂ produced a yellow compound withabsorption maximum at 450 nm. This may correspond to the previouslymisinterpreted assignments for this compound (D. Chun-Ying et al., 1999,J. Coord. Chem., 46:301-312), and the photoproduct is likely to be thecomplex [Ru(bpy)₂(4AP)CH₃CN]²⁺). Several ruthenium polypyridyl complexespresent this behavior. (D. V. Pinnick et al., 1984, Inorg. Chem.,23:1440-1445).

Although at pH 7 the spectrum of the irradiated complex is very similarto that of the original complex, a diminished shoulder at 470 nm becomesevident. To determine the nature of the photoreaction, NMR spectra weretaken before and after irradiation with visible light. FIG. 1 shows thesignal assigned to the meta hydrogens [Ru(bpy)₂(4AP)₂]Cl₂ (m1). Afterirradiation, this signal decreased, and two new signals appeared atlower fields: one corresponding to the free ligand (m3), and the othercorresponding to the aquo-4AP complex (m2), indicating photorelease ofthe 4AP. These two latter signals integrated for 0.30 and 0.27 of theinitial signal, which corresponds to a photoreaction of 60%.

The redox potential of the couple Ru^(III)/Ru^(II) for[Ru(bpy)₂(4AP)₂]Cl₂ measured in water is E=0.76 V versus Ag/AgCl, whichis consistent with the higher basicity of 4AP compared with that ofpyridine. Thus, the redox and the photochemistry of [Ru(bpy)₂(4AP)₂]Cl₂is in total agreement with results obtained corresponding to theRu(bpy)₂XY family, X and Y being monodentate ligands. (See, e.g., E. S.Dodsworth et al., 1986, Chem. Phys. Lett., 124:152-158). Thephotoactivity of these compounds has been explained in terms of areaction pathway that involves the transition between the MLCT state toa lower-energy d-d state, which promotes ligand release. There is adirect correspondence between the energy of the MLCT transition and thequantum yield of the photoreaction. For [Ru(bpy)₂(4AP)CH₃CN]²⁺, thephotoreaction yield is about φ_(PR)=0.4. Since [Ru(bpy)₂(4AP)₂]Cl₂presents a red-shifted band, a lower photoreaction yield is expected. Anestimate based on early experiments leads to an estimate of φ_(PR)≅0.02at 473 nm.

Example 14

Neurophysiological Activity of 4AP Photoreleased from[Ru(bpy)₂(4AP)₂]Cl₂. A standard setup for intracellular voltagemeasurements was used, and the medicinal leech Hirudo medicinalis wasused to demonstrate photoreleased 4AP's neurophysiological activity.Hirudo medicinalis has a central nerve cord with several ganglia, eachone containing about 400 neurons arranged in a known pattern. (W.-R.Schlue et al., 1980, J. Exp. Biol., 82:23-34). An entire ganglion wasmounted on a dish. The transmembrane potential for a single cell (aneuron) in the ganglion was recorded by inserting inside the neuron aglass micropipet with a micrometer-sized end, filled with saturatedaqueous KCl that acts as a luggin bridge for an Ag/AgCl electrode.Another Ag/AgCl electrode was used as a reference. The signal was takenwith an AM-System 1600 amplifier, and the entire setup was covered witha Faraday cage. A 12 bit A/D acquisition card was used to digitize thedata using an ad-hoc program written in QuickBasic.

Low Ca²⁺-high Mg²⁺ saline solution (NaCl, 102 mM; KCl, 4 mM; CaCl₂: 1mM; and MgCl₂: 10 mM; Tris base, pH 5.4 adjusted to 7.4) was perfusedthrough the dish. [Ru(bpy)₂(4AP)₂]Cl₂ and the free ligand 4AP wereinjected in the mainstream at controlled times. A pulsed Xe lamp locatedunder the dish was used to irradiate the solution. UV light was removedusing a band-pass filter at 500 nm. FIG. 2 shows the behavior of themembrane potential recorded at one of the Retzius (Rz) cells in theganglion. The upper graph in FIG. 2 shows the raw data, presentingperiods of rest potential and very fast spikes (action potentials),produced by the changes in membrane ion permeabilities. The lower graphshows the instantaneous spiking frequency at each time.

After impaling the cell with an electrode, many experiments wereperformed on the same cell to ensure reproducibility. After 5000seconds, the cell showed low activity, as can be seen at the left of thegraph. At t=5200 s, ˜100 μM Ru(bpy)₃Cl₂ was added to the salinesolution, without significant changes in activity. 300 seconds later, at5500 s, a light flash was directed to the ganglion. The sudden increasein the frequency of the action potentials is mainly due to thetemperature pulse, but after a short time the activity decreased to thebasal level. After washing by perfusion, further irradiation (t=6000 s)with a pulse showed a very similar pattern. At t=6250 s, ˜100 μM[Ru(bpy)₂(4AP)₂]Cl₂ was added to the saline and the activity remainedunchanged. However, after a new light flash (t=6400 s), sudden activitywas recorded and it remained high after 300 s. A second light pulse at6750 s promoted an even higher activity, which decreased only aftercleaning perfusion with pure saline.

A similar frequency increase occurred when free 4AP was perfused ontothe ganglion, thus demonstrating that the release of 4AP causes thismaintained frequency increase. Calibration of the cell activity usingsolutions of 4AP showed that in each irradiation, 10-15 μM of 4AP werereleased from [Ru(bpy)₂(4AP)₂]Cl₂ during the previous experiments.Neither toxicity nor a deleterious effect was observed on the neuronduring the experiments. These results show that a neuronal response canbe stimulated using [Ru(bpy)₂(4AP)₂]Cl₂, an illustrative PhotolabileCompound, to photorelease an organic molecule having neurophysiologicalactivity.

Example 15

Photorelease of TzGly from [Ru(bpy)₂(TzGly)(py)]Cl₂. The procedure forthe photorelease of TzGly from [Ru(bpy)₂(TzGly)(py)]Cl₂ is analogous tothat used for photorelease of 4AP from [Ru(bpy)₂(4AP)₂]Cl₂ describedabove in Example 13, except that the irradiation light spot was verylocalized (diameter<1 micron). Irradiation of [Ru(bpy)₂(TzGly)(py)]Cl₂at 470 nm photoreleased TzGly.

Example 16

Neurophysiological Activity of TzGly Photoreleased from[Ru(bpy)₂(TzGly)(py)]Cl₂. The neurophysiological activity ofphotoreleased TzGly was assessed by performing experiments similar tothose as set forth above in Example 14. Accordingly, the standard setupfor intracellular voltage measurements was used, and the medicinal leechHirudo medicinalis was used to demonstrate photoreleased TzGly'sneurophysiological activity in the leech ganglion.

All patent applications, published patent applications, issued andgranted patents, texts, and literature references cited in thisspecification are hereby incorporated herein by reference in theirentirety to more fully describe the state of the art to which thepresent invention pertains.

As various changes can be made in the above methods and compositionswithout departing from the scope and spirit of the invention asdescribed, it is intended that all subject matter contained in the abovedescription, shown in the accompanying drawings, or defined in theappended claims be interpreted as illustrative, and not in a limitingsense.

1-32. (canceled)
 33. A compound of Formula II:

wherein M is Ru or Os; each L¹ is independently an organic moleculehaving: (a) a 5-membered monocyclic aromatic ring, one of the ring'smembers being a nitrogen atom that forms a bond with M; (b) a 6-memberedmonocyclic aromatic ring, one of the ring's members being a nitrogenatom that forms a bond with M; (c) an 8-10-membered bicyclic ring, oneof the bicyclic rings being aromatic and having a nitrogen atom memberthat forms a bond with M; (d) an —NH₂ group whose nitrogen atom forms abond with M; or (e) a —COOH group, one of whose oxygen atoms forms abond with M; L² is (R²)₃P, (R²⁰)₃P, or L¹, wherein each R² isindependently —C₁-C₁₈ alkyl, —C₃-C₈ cycloalkyl, or phenyl, and m is 2;or L² is —CN and m is 1; R¹-R⁸ are independently —H, —C₁-C₁₈ alkyl,—NH₂, —COOH, —(C₁-C₁₈ alkyl)-O—(C₁-C₁₈ alkyl), or —OC(O)(C₁-C₁₈ alkyl);and X is Cl⁻, F⁻, Br⁻, I⁻, PF₆ ⁻, CF₃SO₃ ⁻, (C₁-C₁₈ alkyl)-CO₂ ⁻, or(C₁-C₁₈ alkyl)-SO₃ ⁻.
 34. The compound of claim 33, wherein the organicmolecule is 4-aminopyridine.
 35. The compound of claim 33, wherein theorganic molecule is (RS)-(tetrazol-5-yl) glycine.
 36. The compound ofclaim 33, wherein the organic molecule is (tetrazol-5-yl) AMPA.
 37. Thecompound of claim 33, wherein the organic molecule is nicotine orcaffeine.
 38. The compound of claim 33, wherein the organic molecule isserotonin, epinephrine, norepinephrine, or dopamine.
 39. The compound ofclaim 33, wherein the organic molecule is adenosine 5′-diphosphate ADP,adenosine 5′-triphosphate ATP, adenosine 5′-monophosphate AMP, cyclicadenosine 5′-diphosphate ribose, or adenosine 3′,5′-cyclicmonophosphate.40. The compound of claim 33, wherein the organic molecule isaminobutyric acid or L-glutamic acid, or methyl-D-aspartic acid.
 41. Amethod for releasing an organic molecule from a Photolabile Compound,comprising: exposing a compound of claim 33 to light under conditionssufficient to release the organic molecule. 42-45. (canceled)
 46. Themethod of claim 41, wherein the light comprises visible light orinfrared light.
 47. (canceled)
 48. A method for protecting an organicmolecule from an effect of an enzyme, comprising: allowing the organicmolecule and a compound of Formula II′:

wherein m is 2, R¹-R⁸ are independently —H, —C₁-C₁₈ alkyl, —NH₂, —COOH,—(C₁-C₁₈ alkyl)-O—(C₁-C₁₈ alkyl), or —OC(O)(C₁-C₁₈ alkyl); and X is Cl⁻,F⁻, Br⁻, I⁻, PF₆ ⁻, CF₃SO₃ ⁻, (C₁-C₁₈ alkyl)-CO₂ ⁻, or (C₁-C₁₈alkyl)-SO₃ ⁻, to react under conditions sufficient to make a compound ofclaim 33, wherein the organic molecule has: (a) a 5-membered monocyclicaromatic ring, one of the ring's members being a nitrogen atom thatforms a bond with M; (b) a 6-membered monocyclic aromatic ring, one ofthe ring's members being a nitrogen atom that forms a bond with M; (c)an 8-10-membered bicyclic ring, one of the bicyclic rings being aromaticand having a nitrogen atom member that forms a bond with M; (d) an —NH₂group whose nitrogen atom forms a bond with M; or (e) a POOH group, oneof whose oxygen atoms forms a bond with M.
 49. A method for making anorganic molecule bioavailable to a subject, comprising: (a)administering a compound of claim 33 to the subject; and (b) exposingthe compound to light under conditions sufficient to release the organicmolecule from the compound, wherein the organic molecule has: (i) a5-membered monocyclic aromatic ring, one of the ring's members being anitrogen atom that forms a bond with M; (ii) a 6-membered monocyclicaromatic ring, one of the ring's members being a nitrogen atom thatforms a bond with M; (iii) an 8-10-membered bicyclic ring, one of thebicyclic rings being aromatic and having a nitrogen atom member thatforms a bond with M; (iv) an —NH₂ group whose nitrogen atom forms a bondwith M; or (v) a POOH group, one of whose oxygen atoms forms a bond withM.
 50. The method of claim 49, wherein the light is sunlight,photo-optic light, or laser light.
 51. The method of claim 49, whereinthe light is visible light or infrared light.
 52. The method of claim49, wherein the exposing occurs at the site of a tumor, cancer, orneoplasm.
 53. The method of claim 49, wherein the administering occursintravenously, topically, intradermally, intramuscularly, transdermally,subcutaneously, intranasally, parenterally, intrathecally, vaginally,rectally, colorectally, orally, intracranially, retroorbitally,intrasternally, or by injection.
 54. (canceled)
 55. A compositioncomprising a compound of claim 33 and a physiologically acceptablecarrier, vehicle, diluent, or excipient. 56-63. (canceled)
 64. A kitcomprising a compound of claim 33 and instructions for use of thecompound. 65-96. (canceled)
 97. A compound of Formula IVa:

wherein: each L¹ is independently an organic molecule having: (a) atetrazolyl group, one of its nitrogen atoms forming a bond with Ru; (b)nicotine or caffeine, whose pyridyl nitrogen atom forms a bond with Ru;(c) an 8-10-membered bicyclic ring, one of the bicyclic rings beingaromatic and having a nitrogen atom member that forms a bond with Ru;(d) an —NH₂ group whose nitrogen atom forms a bond with Ru; or (e) a—COOH group, one of whose oxygen atoms forms a bond with Ru; L¹ is(R²)₃P, (R²⁰)₃P, or L¹, wherein each R² is independently —C₁-C₁₈ alkyl,—C₃-C₈ cycloalkyl, or phenyl, and m is 2; or L² is —CN and m is 1; R¹ toR⁸ are independently —H, —C₁-C₁₈ alkyl; —NH₂, —COOH, —(C₁-C₁₈alkyl)-O—(C₁-C₁₈ alkyl), or —OC(O)(C₁-C₁₈ alkyl); and X is Cl⁻, F⁻, Br⁻,I⁻, PF₆ ⁻, CF₃SO₃ ⁻, (C₁-C₁₈ alkyl)-CO₂ ⁻, or (C₁-C₁₈ alkyl)-SO₃ ⁻. 98.The compound of claim 97, wherein the organic molecule is(RS)-(tetrazol-5-yl) glycine.
 99. The compound of claim 97, wherein theorganic molecule is (tetrazol-5-yl) AMPA.
 100. The compound of claim 97,wherein the organic molecule is nicotine or caffeine.
 101. The compoundof claim 97, wherein the organic molecule is serotonin, epinephrine,norepinephrine, or dopamine.
 102. The compound of claim 97, wherein theorganic molecule is adenosine 5′-diphosphate ADP, adenosine5′-triphosphate ATP, adenosine 5′-monophosphate AMP, cyclic adenosine5′-diphosphate ribose, or adenosine 3′,5′-cyclicmonophosphate.
 103. Thecompound of claim 97, wherein the organic molecule is aminobutyric acidor L-glutamic acid, or methyl-D-aspartic acid.
 104. A method forreleasing an organic molecule from a Photolabile Compound, comprising:exposing a compound of claim 97 to light under conditions sufficient torelease the organic molecule. 105-110. (canceled)
 111. A method forprotecting an organic molecule from an effect of an enzyme, comprising:allowing the organic molecule and a compound of Formula IVa′:

wherein m is 2; R¹ to R⁸ are independently —H, —C₁-C₁₈ alkyl; —NH₂,—COOH, —(C₁-C₁₈ alkyl)-O—(C₁-C₁₈ alkyl), or —OC(O)(C₁-C₁₈ alkyl); and Xis Cl⁻, F⁻, Br⁻, I⁻, PF₆ ⁻, CF₃SO₃ ⁻, (C₁-C₁₈ alkyl)-CO₂—, or (C₁-C₁₈alkyl)-SO₃ ⁻, to react under conditions sufficient to make a compound ofclaim 97, wherein the organic molecule has: (a) a tetrazolyl group, oneof its nitrogen atoms forming a bond with Ru; (b) nicotine or caffeine,whose pyridyl nitrogen atom forms a bond with Ru; (c) an 8-10-memberedbicyclic ring, one of the bicyclic rings being aromatic and having anitrogen atom member that forms a bond with Ru; (d) an —NH₂ group whosenitrogen atom forms a bond with Ru; or (e) a —COOH group, one of whoseoxygen atoms forms a bond with Ru.
 112. A method for making an organicmolecule bioavailable to a subject, comprising: (a) administering acompound of claim 97 to the subject; and (b) exposing the compound tolight under conditions sufficient to release the organic molecule fromthe compound, wherein the organic molecule has: (i) a tetrazolyl group,one of its nitrogen atoms forming a bond with Ru (ii) nicotine orcaffeine, whose pyridyl nitrogen atom forms a bond with Ru; (iii) an8-10-membered bicyclic ring, one of the bicyclic rings being aromaticand having a nitrogen atom member that forms a bond with Ru; (iv) an—NH₂ group whose nitrogen atom forms a bond with Ru; or (v) a —COOHgroup, one of whose oxygen atoms forms a bond with Ru.
 113. The methodof claim 112, wherein the light is sunlight, photo-optic light, or laserlight.
 114. The method of claim 112, wherein the light is visible lightor infrared light.
 115. The method of claim 112, wherein the exposingoccurs at the site of a tumor, cancer, or neoplasm.
 116. The method ofclaim 112, wherein the administering occurs intravenously, topically,intradermally, intramuscularly, transdermally, subcutaneously,intranasally, parenterally, intrathecally, vaginally, rectally,colorectally, orally, intracranially, retroorbitally, intrasternally, orby injection.
 117. (canceled)
 118. A composition comprising a compoundof claim 97 and a physiologically acceptable carrier, vehicle, diluent,or excipient. 119-126. (canceled)
 127. A kit comprising a compound ofclaim 97 and instructions for use of the compound.
 128. A compound ofFormula IVb:

wherein: L¹ is 4-aminopyridine, whose pyridyl nitrogen atom forms a bondwith Ru; L² is (R²)₃P, (R²⁰)₃P, or L¹, wherein each R² is independently—C₁-C₁₈ alkyl, —C₃-C₈ cycloalkyl, or phenyl, and m is 2; or L² is —CNand m is 1; R¹ to R⁸ are independently —H, —C₁-C₁₈ alkyl, —NH₂, —COOH,—(C₁-C₁₈ alkyl)-O—(C₁-C₁₈ alkyl), or —OC(O)(C₁-C₁₈ alkyl); and X is Cl⁻,F⁻, Br⁻, I⁻, PF₆ ⁻, CF₃SO₃ ⁻, (C₁-C₁₈ alkyl)-CO₂ ⁻, or (C₁-C₁₈alkyl)-SO₃ ⁻.
 129. A method for releasing an organic molecule from aPhotolabile Compound, comprising: exposing a compound of claim 128 tolight under conditions sufficient to release the organic molecule.130-133. (canceled)
 134. The method of claim 128, wherein the lightcomprises visible light or infrared light.
 135. (canceled)
 136. A methodfor protecting an organic molecule from an effect of an enzyme,comprising: allowing the organic molecule and a compound of FormulaIVb′:

wherein m is 2; R¹ to R⁸ are independently —H, —C₁-C₁₈ alkyl; —NH₂,—COOH, —(C₁-C₁₈ alkyl)-O—(C₁-C₁₈ alkyl), or —OC(O)(C₁-C₁₈ alkyl); and Xis Cl⁻, F⁻, Br⁻, F⁻, PF₆ ⁻, CF₃SO₃ ⁻, (C₁-C₁₈ alkyl)-CO₂—, or (C₁-C₁₈alkyl)-SO₃ ⁻, to react under conditions sufficient to make a compound ofclaim 129, wherein the organic molecule 4-aminopyridine, whose pyridylnitrogen atom forms a bond with Ru.
 137. A method for making an organicmolecule bioavailable to a subject, comprising: (a) administering acompound of claim 128 to the subject; and (b) exposing the compound tolight under conditions sufficient to release the organic molecule fromthe compound, wherein the organic molecule is molecule 4-aminopyridine(4-AP), whose pyridyl nitrogen atom forms a bond with Ru.
 138. Themethod of claim 137, wherein the light is sunlight, photo-optic light,or laser light.
 139. The method of claim 137, wherein the light isvisible light or infrared light.
 140. The method of claim 137, whereinthe exposing occurs at the site of a tumor, cancer, or neoplasm. 141.The method of claim 137, wherein the administering occurs intravenously,topically, intradermally, intramuscularly, transdermally,subcutaneously, intranasally, parenterally, intrathecally, vaginally,rectally, colorectally, orally, intracranially, retroorbitally,intrasternally, or by injection.
 142. (canceled)
 143. A compositioncomprising a compound of claim 128 and a physiologically acceptablecarrier, vehicle, diluent, or excipient. 144-151. (canceled)
 152. A kitcomprising a compound of claim 128 and instructions for use of thecompound.
 153. A compound of Formula V:

wherein M¹ is Li⁺, Na⁺, or K⁺; and M² is Fe, Ru, or Os; and L¹ isindependently an organic molecule having: (a) a 5-membered monocyclicaromatic ring, one of the ring's members being a nitrogen atom thatforms a bond with M²; (b) a 6-membered monocyclic aromatic ring, one ofthe ring's members being a nitrogen atom that forms a bond with M²; (c)an 8-10-membered bicyclic ring, one of the bicyclic rings being aromaticand having a nitrogen atom member that forms a bond with M²; (d) an —NH₂group whose nitrogen atom forms a bond with M 2; or (e) a —COOH group,one of whose oxygen atoms forms a bond with M²; and X is Cl⁻, F⁻, Br⁻,I⁻, PF₆ ⁻, CF₃SO₃ ⁻, (C₁-C₁₈ alkyl)-CO₂ ⁻, or (C₁-C₁₈ alkyl)-SO₃ ⁻. 154.The compound of claim 153, wherein the organic molecule is4-aminopyridine.
 155. The compound of claim 153, wherein the organicmolecule is (RS)-(tetrazol-5-yl) glycine.
 156. The compound of claim153, wherein the organic molecule is (tetrazol-5-yl) AMPA.
 157. Thecompound of claim 153, wherein the organic molecule is nicotine orcaffeine.
 158. The compound of claim 153, wherein the organic moleculeis serotonin (5-hydroxy triptamine), epinephrine, norepinephrine, ordopamine.
 159. The compound of claim 153, wherein the organic moleculeis adenosine 5′-diphosphate ADP, adenosine 5′-triphosphate ATP,adenosine 5′-monophosphate AMP, cyclic adenosine 5′-diphosphate ribose,or adenosine 3′,5′-cyclicmonophosphate.
 160. The compound of claim 153,wherein the organic molecule is aminobutyric acid or L-glutamic acid, ormethyl-D-aspartic acid.
 161. A method for releasing an organic moleculefrom a Photolabile Compound, comprising: exposing a compound of claim153 to light under conditions sufficient to release the organicmolecule.
 162. The method of claim 161, wherein the light comprises awavelength of about 300 to about 500 nm.
 163. The method of claim 162,wherein the light comprises a wavelength of about 300 to about 360 nm.164. The method of claim 162, wherein the light comprises a wavelengthof about 450 to about 500 nm.
 165. The method of claim 161, wherein thelight comprises visible light or infrared light.
 166. (canceled)
 167. Amethod for protecting an organic molecule from an effect of an enzyme,comprising: allowing the organic molecule and a compound of Formula V′:

wherein M¹ is Li⁺, Na⁺, or K⁺; and M² is Fe, Ru, or Os, to react underconditions sufficient to make a compound of claim 154, wherein theorganic molecule has: (a) a 5-membered monocyclic aromatic ring, one ofthe ring's members being a nitrogen atom that forms a bond with M; (b) a6-membered monocyclic aromatic ring, one of the ring's members being anitrogen atom that forms a bond with M; (c) an 8-10-membered bicyclicring, one of the bicyclic rings being aromatic and having a nitrogenatom member that forms a bond with M; (d) an —NH₂ group whose nitrogenatom forms a bond with M; or (e) a —COOH group, one of whose oxygenatoms forms a bond with M.
 168. A method for making an organic moleculebioavailable to a subject, comprising: (a) administering a compound ofclaim 153 to the subject; and (b) exposing the compound to light underconditions sufficient to release the organic molecule from the compound,wherein the organic molecule has: (i) a 5-membered monocyclic aromaticring, one of the ring's members being a nitrogen atom that forms a bondwith M; (ii) a 6-membered monocyclic aromatic ring, one of the ring'smembers being a nitrogen atom that forms a bond with M; (iii) an8-10-membered bicyclic ring, one of the bicyclic rings being aromaticand having a nitrogen atom member that forms a bond with M; (iv) an —NH₂group whose nitrogen atom forms a bond with M; or (v) a —COOH group, oneof whose oxygen atoms forms a bond with M.
 169. The method of claim 168,wherein the light is sunlight, photo-optic light, or laser light. 170.The method of claim 168, wherein the light is visible light or infraredlight.
 171. The method of claim 168, wherein the exposing occurs at thesite of a tumor, cancer, or neoplasm.
 172. The method of claim 168,wherein the administering occurs intravenously, topically,intradermally, intramuscularly, transdermally, subcutaneously,intranasally, parenterally, intrathecally, vaginally, rectally,colorectally, orally, intracranially, retroorbitally, intrasternally, orby injection.
 173. (canceled)
 174. A composition comprising a compoundof claim 153 and a physiologically acceptable carrier, vehicle, diluent,or excipient. 175-182. (canceled)
 183. A kit comprising a compound ofclaim 153 and instructions for use of the compound.
 184. A method forassaying an organic molecule, comprising exposing a Photolabile Compoundof any one of claims 1, 33, 65, 97, 128, or 153 to light underconditions sufficient to release the organic molecule from thePhotolabile Compound, and (b) determining an effect of the organicmolecule on a biological sample.